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2001 Fruit and Vegetable Crops Research Report
Introduction ! Tree Fruits ! Small Fruits ! Vegetables ! Greenhouse Production ! Diagnostic Laboratory ! Appendix

Vegetables

Bell and Specialty Pepper Evaluations for Bacterial Spot Resistance, Yield, and Quality

Brent Rowell, R. T. Jones, W. Nesmith, A. Satanek, W. Turner, and J.C. Snyder, Department of Horticulture

Introduction

After completing a three-year (1995-97) evaluation of bell pepper cultivars under induced bacterial spot (Xanthomonas campestris pv. vesicatoria or Xcv) and bacterial spot-free environments, we began a new series of trials in 2000 to compare new cultivars with previously recommended cultivars that were either highly resistant (`Boynton Bell') and/or that had very attractive fruits (`X3R Wizard'). While spot-resistant pepper cultivars with the Bs2 gene (resistance to Xcv races 1, 2, and 3) gained widespread acceptance in the state, a number of new resistant cultivars has been released since 1997. In addition to bells, we also wanted to screen a large number of hot and specialty peppers, some of which also carry the Bs2 gene. Out-of-state buyers have expressed a strong interest in sourcing hot and specialty peppers from Kentucky. Bell varieties were tested again in replicated trials at two locations in 2001, while hot and specialty peppers were observed for a second year in non-replicated `RACE' trials at the same locations.

Materials and Methods

Near-duplicate trials were planted at the Horticultural Crops Research Station in Lexington (LEX) and at an isolated location in Eastern Kentucky at the Robinson Experiment Station in Quicksand (QSND). Sixteen bell and 46 hot and specialty pepper cultivars were seeded in the greenhouse at LEX on 26 March. Seedlings were grown in 72-cell plastic trays and transplanted to the field on 16 May (LEX). Fourteen of the same bell cultivars and all of the same hot/specialty cultivars were transplanted at QSND on 29-30 May. Each LEX trial received 62 lb N/acre prior to planting supplemented by an additional 38 lb N/acre divided into three weekly fertigations from 27 June to 12 July (100 lb N/acre season total). Trials at QSND received preplant applications of 50 lb N/acre supplemented by 60 lb N/acre divided into four fertigations applied from 13 June to 20 July (110 lb N/acre season total). Phosphorus and potassium were applied prior to planting at both locations according to soil test recommendations.

Plots at both locations consisted of 16 plants in double rows with four replications in a randomized complete block design for bells and in single plots for hot and specialty peppers. All were planted on raised beds with black plastic mulch and drip irrigation. Plants of all cultivars were spaced 12 inches apart in the row with 15 inches between the two rows on each bed. Beds were 6 feet apart from center to center. A tank mix of maneb+fixed copper was applied weekly for bacterial spot (BLS) protection at Lexington.

No preventive fungicide treatments were applied at QSND in order to encourage the development of a natural BLS epidemic. No insecticides were required in the field at LEX or QSND. A pheromone trap for adult male European corn borers was placed adjacent to the trial field at LEX.

Thirteen new bell cultivars with the Bs2 gene were compared with resistant controls `Boynton Bell' and `X3R Wizard' and with a susceptible control, `King Arthur' (Bs1 only, Table 1). The 13 new cultivars included seven from the 2000 trial and six that were tested for the first time in 2001. Mature green fruits were harvested four times in LEX and twice at QSND.

Marketable fruits were graded and weighed according to size class (U.S. No. 1 extra large, large, medium). We also weighed misshapen fruits that could be marketed to foodservice as "choppers" (LEX only). Yields in each size class were multiplied by their respective wholesale market prices to determine gross returns ("income") for each cultivar. The income variable has been a good indicator of a cultivar's overall performance, taking into account yields of the different size classes and their price differentials. Prices from 2000 were also used for the 2001 trials.

Hot and specialty peppers included a group of 13 jalapeño cultivars of which two had the Bs2 resistance gene (`X3R Ixtapa' and `El Rey'= SAX 7603) and others claiming multiple virus resistance (Table 3). These were compared with `Mitla'. Other pepper types included were three serrano cultivars, six anaheim cultivars, seven poblano/ancho cultivars (entry SVR 35-4845-7 has the Bs2 gene), four Italian/cubanelle cultivars, four hot banana/wax cultivars (X3R Hot Spot and SVR 35-4846-7 with Bs2 gene), six sweet banana/wax cultivars (`Pageant', `Sweet Spot', and PX 35-4360-7 with Bs2 gene), two fresno cultivars, and two pepperoncini cultivars (Tables 4 and 5).

Fruit appearance ratings. All bell pepper fruits harvested from all replications at the second harvest (July 19) at LEX were laid out in the field for careful examination and quality ratings. All fruits from single plots of hot and specialty pepper cultivars were evaluated in the same way at LEX on July 30. Bell pepper fruits from two replications were evaluated at QSND (August 9, first harvest). Overall appearance ratings took several things into account, including, in order of importance, overall attractiveness, shape, smoothness, degree of "flattening" (bell cultivars only), color, and uniformity of shape.

Plant support requirements. Some of the hot and specialty pepper cultivars required staking and tying in these trials that used close spacings, double rows, and plastic mulch with drip irrigation. All specialty cultivars at LEX were inspected at maximum fruit load to determine if staking and tying were needed; those requiring support are indicated in Tables 4 and 5. Tomato stakes (shorter stakes could also have been used) were driven into the ground at the four corners of individual plots; plants were "fenced in" by running a string (tomato twine) around these four stakes. A single stringing was adequate for some cultivars, while others required two or three successive stringings.

Inoculation and Disease Assessment

As in previous years, LEX plots were sprayed weekly with copper+maneb to help protect against bacterial spot, while QSND plots were left unsprayed in order to encourage the development of a natural epidemic. June weather conditions in QSND were very favorable for BLS epidemic development, and a natural epidemic did occur early in the season. Bell and specialty cultivars were assessed only once at QSND for BLS symptoms on June 28. Symptoms were extensive and severe on some cultivars in the hot and specialty trial by that date. BLS symptoms were scored as follows: 0 = no symptoms, 1 = very few (trace) symptoms visible, 2 = symptoms obvious but not extensive, and 4 = extensive symptoms (plants severely affected). These observations were made prior to the inoculation attempt described below.

In order to encourage a more uniform BLS epidemic within the trial, an attempt was made to inoculate all bell cultivars with inoculum collected from the hot pepper trial. About 300 leaves with typical symptoms were collected at random from various susceptible cultivars within the hot pepper trial plot on 27 June. These were placed in a plastic bucket with sufficient distilled water to cover the leaves. The mixture was stirred for about 10 minutes with a wooden stick to enhance extraction of the bacteria, making an effort to crush some leaves on the side of the bucket. The mixture was then poured through a cotton bag to remove leaf debris and squeezed by hand. Two gallons of this mixture were diluted further with water to make a total volume of 4 gallons. This mixture was applied uniformly to all plants in the bell pepper trial using a hand-operated sprayer. The inoculation attempt was made in late afternoon, within 15 minutes of the extraction. Heavy rains had preceded the inoculation attempt; the ground and foliage were wet during the inoculation and remained wet until mid-morning the following day. We considered this procedure to be a relatively simple means of ensuring more uniform epidemics using only races of the bacterium already found within the trial; we have successfully used this method in trials with other crops in the past.

About three hours after the inoculations, some of the mixture remaining in the sprayer was applied to pepper seedlings growing in a greenhouse on the Lexington campus. These seedlings developed extensive BLS symptoms within 10 days.

Results and Discussion

As in previous years, we wanted to encourage disease and evaluate resistance at QSND while keeping the LEX trial free of bacterial spot. No bacterial spot symptoms were observed in the bell or hot/specialty trials in LEX.

Bell cultivars. Total marketable yields, gross incomes, and fruit quality characteristics for bell cultivars grown without bacterial spot at LEX are shown in Table 1. Although yields were somewhat lower than in 2000, most of the cultivars were high yielding (20 to 25 tons/acre) at LEX with nine that were not significantly different from the top-yielding cultivar `X3R Aristotle' (Table 1). `Aristotle', `King Arthur' (bacterial spot susceptible), `4 Star', `Boynton Bell', and `Lexington' were also in this category in the 2000 LEX trial.

Yields, income, and fruit quality characteristics for most of the same cultivars grown at QSND are shown in Table 2. While an early bacterial spot epidemic did occur in the trial at this location, it had ended abruptly and inexplicably by the second week in July. No new bacterial spot lesions developed in the field at QSND after the inoculation attempt. In fact, all bacterial spot activity suddenly stopped in both the inoculated trial and the adjacent hot pepper trial that had not been inoculated. The reasons for this failure are not understood but may be the result of environmental factors. Night temperatures below 61°F are known to suppress bacterial spot development regardless of daytime temperatures. Nights were unusually cool from 12-17 July (57°F was the average night temperature for that period). In addition, although the plots were still soaked from heavy rains prior to inoculation, rainfall did not occur again until eight days after the inoculation.

There were no statistically significant differences among cultivars for total marketable yields or gross incomes at QSND. Marketable yields ranged from 13 to18 tons per acre (Table 2). Some of the highest yielding cultivars at QSND were also in the highest yielding group of varieties tested at LEX: `4 Star', `X3R Aristotle', `X3R Red Knight'. Yields appeared to have been affected by the early bacterial spot epidemic. `King Arthur' and `X3R Wizard' were among the lowest-yielding cultivars at this location; these cultivars have been among the most susceptible in previous trials exposed to natural and induced BLS epidemics at QSND.

Scores for BLS symptom development from the 28 June assessment were extremely variable (c.v. = 116 percent), and no statistically significant differences were detected among cultivars (data not shown). This single assessment did not provide enough information to make valid comparisons for BLS resistance among cultivars. `Conquest', a cultivar with the Bs2 gene, had the highest average score for BLS symptoms at this first and only assessment date.

While BLS symptoms had nearly disappeared by the third week in July, leaf spots caused by Phyllosticta sp. were evident on many of the bell and specialty cultivars by July 11.

Fruit quality characteristics for bell cultivars are also shown in Tables 1 and 2. `Aristotle' and `Defiance' received the highest fruit appearance ratings at LEX, which were better than ratings for `X3R Wizard'. `Aristotle', `Lexington', `Defiance', and `X3R Wizard' had the darkest green fruits in the LEX trial. `Defiance', `X3R Wizard', and `X3R Red Knight' received the best appearance scores at QSND. Many other cultivars received acceptable appearance ratings (6 or above at LEX or 5 and above at QSND) while `King Arthur', `Boynton Bell', `X3R Red Knight', `Conquest', and PR99Y-3 were rated lower than the others at LEX. `X3R Aristotle' scored lower in overall appearance at QSND than at LEX. `King Arthur' had the lowest score at QSND. `King Arthur' has had consistently low fruit appearance scores in a number of trials; we consider it and similar cultivars better suited to foodservice markets.

Cultivars that were the highest yielding and that had acceptable or better fruit quality ratings at both locations included `X3R Aristotle', `4 Star', and `Orion'. A possible disadvantage of a cultivar like `4 Star' was its light to medium green-colored fruits (also light green in the 2000 trial); it may be difficult to market these lighter colored cultivars when buyers have become accustomed to receiving those with darker fruits like `X3R Wizard'.

Jalapeños. Yields and fruit characteristics of the 13 jalapeño pepper cultivars grown in single plots at LEX and QSND are shown in Table 3. Two of these cultivars carried the Bs2 gene for bacterial spot resistance. Most jalapeño cultivars had high marketable yields at LEX ranging from 14 to 27 tons per acre with three cultivars exceeding `Mitla' (Table 3). Among these `Coyame', `Summer Heat 6000', and RPP 7042-VP had the most attractive fruits.

Cultivars were exposed to a natural bacterial spot epidemic early in the season at QSND; however, the epidemic had nearly disappeared by mid-July and only a single assessment for symptoms was obtained. Unlike results from the 2000 jalapeño trial, the two cultivars with the Bs2 gene and `Jalandro' appeared to be most affected by this short-lived epidemic (Table 3).

Serranos. Marketable yields for the three serrano cultivars at LEX ranged from 15 to 22 tons per acre with `Tuxtlas' and `Serrano del Sol' having the highest yields and most attractive fruits (Table 4). `Tuxtlas' was also the highest yielding and most attractive serrano in 2000.

Anaheims. Yields of the six anaheim cultivars ranged from 15 to 31 tons per acre at LEX; `Novajoa' was the highest yielding while PX-35-4606-7 and `Anaheim TMR 23' had the most attractive fruits (Table 4). `Novajoa' was also highest yielding at QSND in spite of severe BLS symptoms early in the season (Table 4).

Poblano/anchos. Yields among the seven poblano cultivars at LEX ranged from 4 to 21 tons per acre. `Ancho Villa' was again (as in 2000) the highest yielding with the largest fruit size (Table 4); fruits of this cultivar, however, were lighter colored, which could possibly be a disadvantage in some markets. The only entry with the Bs2 gene for resistance to bacterial spot (SVR 35-4845-7) was high yielding and had the highest appearance rating at LEX. Most poblano/ancho cultivars are quite susceptible to bacterial spot, and yields at QSND may have been affected by the early epidemic at this location (Table 4). `Mulato Isleno' had very low yields at both locations.

Italian/cubanelles. Yields for the four Italian/cubanelle or frying peppers ranged from 17 to 28 tons per acre at LEX (Table 4). `Aruba' had the highest yield and largest fruit size followed by `ACX 500'. As in 2000, `Corno di Toro' was considered to have the most attractive fruits, although they were light to medium green in color instead of the typical light green or pale yellow. `Key West', a new cultivar with the resistance to bacterial spot, appeared to be unaffected by the early epidemic at QSND (Table 4).

Hot banana/wax. Two hot banana cultivars and `Santa Fe Grande' were tested. `X3R Hot Spot' (with the Bs2 gene) had the highest marketable yield and good appearance ratings at LEX (26 tons/acre, Table 5). Both `Inferno' and `Santa Fe Grande' had severe symptoms of bacterial spot associated with the early epidemic at QSND.

Sweet banana/wax. The six sweet banana or sweet wax cultivars included two with the Bs2 gene (`Pageant' and PX 35-4360-7); yields at LEX ranged from 21 to 32 tons per acre (Table 5). PX 35-4360-7 was the highest yielding entry at both locations and had the most attractive fruits. Most cultivars had many "C"—or apostrophe-shaped—fruits. `Market Sweet' was high yielding at LEX but exhibited severe BLS symptoms during the brief epidemic at QSND.

Fresno and pepperoncini. Two fresno cultivars—one with upright fruits and one with pendant fruits—were included in the trials. Marketable yield was higher and fruit size larger for the upright type (Table 5). `Pepperoncini' from Rupp Seed Company was the highest yielding of the two pepperoncini types tested at LEX. PX 17494 had more attractive fruits at LEX and had higher yields at QSND. The authors are not familiar with market requirements for pepperoncini types; these are usually brined and sold with pizza. Perhaps "C"-shaped pepperoncini fruits could be as desirable as straight fruits.

Pepper types, cultivars, and bacterial spot risk. Kentucky pepper growers experienced periodic devastating bacterial spot epidemics prior to the widespread planting of resistant cultivars after 1995. There is growing interest in Kentucky and other states in growing hot and specialty pepper cultivars, many of which do not carry any major resistance genes. While there is a significant risk of bacterial spot epidemics associated with the production of some of these cultivars, others can be grown with less likelihood of disaster, especially with a sound spray regimen. Relative bacterial spot risks for various pepper types and cultivars were estimated after the 2000 trials and are shown in Table 6. Our recommendation remains that growers use resistant cultivars whenever possible in conjunction with copper+maneb preventive spray programs.

Acknowledgment

The authors would especially like to thank Darrell Slone, Janet Pfeiffer, Amanda Ferguson, Dave Lowry, Bonnie McCaffrey, Larry Blandford, Spencer Helsabeck, and John Holden for their hard work and generous assistance with these trials.

Table 1. Yields, gross returns, and appearance of bell pepper cultivars under bacterial spot-free conditions in Lexington, Ky.; yield and returns data are means of four replications.
Cultivar Seed source Tot. mkt. yield1 (tons/A) % XL + Large2 Income3 ($/acre) Shape unif.4 Overall appear.5 No. lobes6 Fruit color Comments
X3R Aristotle S 25.0 89 10,180 4 7 3 dk green most fruits longer than wide
King Arthur S 22.5 88 9,079 3 5 4 light-med green deep blossom-end cavities
4 Star RG 22.2 86 9,111 3.5 6 4 light-med green
Boynton Bell HM 21.7 92 9,003 3 5 3 med-dk green ~15% of fruits 2-lobed (pointed)
Corvette S 20.6 88 8,407 3 6 3&4 med-dk green ~10% elongated (2-lobed)
X3R Red Knight S 20.5 90 8,428 3 5 4 med-dk green
SP 6112 SW 20.2 78 8,087 4 6 3 med green
Conquest HM 20.0 85 8,021 2 5 3&4 light-med green deep stem-end cavities, many misshapes
Orion EZ 20.0 93 8,219 4 6 4 med-dk green
Lexington S 19.8 87 8,022 3.5 6 3 dk green
PR99Y-3 PR 19.5 87 7,947 3 5 3&4 med green many misshapen fruits
Defiance S 18.7 87 7,568 4 7 3&4 dk green
X3R Ironsides S 18.4 92 7,585 4 6 3 med green ~5% w/deep stem-end cavities
X3R Wizard S 18.0 92 7,447 3 6 3&4 dk green
RPP 9430 RG 17.3 89 7,029 3 6 4 med-dk green ~10% of fruits elongated
ACX 209 AC 17.2 89 7,035 3.5 6 3 med green
Waller-Duncan LSD (P<0.05) 5.2 7 2,133
1 Total marketable yield included yields of U.S. Fancy and No. 1 fruits of medium (>2.5 in. diameter) size and larger plus misshapen but sound fruit which could be sold as "choppers" to foodservice buyers.
2 Percentage of total yield that was extra-large (>3.5 in. diameter) and large (>3 in. diameter but # 3.5 in. diam.).
3 Income = gross returns per acre; average 2000 season local wholesale prices were multiplied by yields from different size/grade categories: $0.21/lb for extra-large and large, $0.16/lb for mediums, and $0.13/lb for "choppers," i.e. misshapen fruits.
4 Average visual uniformity of fruit shape where 1 = least uniform, 5 = completely uniform.
5 Visual fruit appearance rating where 1 = worst, 9 = best, taking into account overall attractiveness, shape, smoothness, degree of flattening, color, and shape uniformity; all fruits from all four replications observed at the second harvest (July 19).
6 3&4 = about half and half 3- and 4-lobed; 3 = mostly 3-lobed; 4 = mostly 4-lobed.

Table 2. Yields, gross returns, and appearance of bell pepper cultivars at Quicksand, Ky.; yield and returns data are means of four replications. All cultivars except King Arthur have the Bs2 gene for resistance to bacterial spot races 1, 2, and 3.
Cultivar Seed source Tot. mkt. yield1 (tons/A) % XL + Large2 Income3 ($/acre) Shape unif.4 Overall appear.5 No. lobes6 Fruit color Comments
4 Star RG 18.4 86 7,496 -- -- -- -- --
X3R Red Knight S 18.0 90 7,344 3 6 3 med green earlier maturing; some red fruits
Defiance S 17.8 87 7,256 3.5 7 3&4 med-dk green nice blocky fruits
X3R Aristotle S 17.4 90 7,164 3 5 3 med-dk green some 2-lobed fruits
RPP 9430 RG 17.3 88 7,105 -- -- -- -- --
X3R Ironsides S 16.7 83 6,794 2 5 3 light-med green some 2-lobed
PR99Y-3 PR 16.0 86 6,508 3 5 3 light-med green deep stem end; some 2-lobed
Conquest HM 15.9 91 6,560 3 5 3 med green slightly elongated; some red fruits
Orion EZ 15.8 86 6,486 3 5 3 med green
SP 6112 SW 15.5 81 6,290 3 5 3 med-dk green many small fruits
Corvette S 15.1 86 6,194 3.5 5 3 med green some 2-lobed
Boynton Bell HM 14.9 77 5,978 3 5 3 med green
ACX 209 AC 14.7 82 5,994 3 5 2,3,46 med green many 2&3-lobed fruits; elongated
King Arthur S 14.3 77 5,746 2 4 3&4 med green
Lexington S 13.6 82 5,520 3 5 3 dk green many small and flattened fruits
X3R Wizard S 12.8 90 5,289 4 6 3&4 dk green nice; slightly elongated
Waller-Duncan LSD (P<0.05) ns 12.2 ns
1 Total marketable yield included yields of U.S. Fancy and No. 1 fruits of medium (>2.5 in. diameter) size and larger.
2 Percentage of total yield that was extra-large (>3.5 in. diameter) and large (>3 in. diameter but # 3.5 in. diam.).
3 Income = gross returns per acre; average 2000 season local wholesale prices were multiplied by yields from different size/grade categories: $0.21/lb for extra-large and large, $0.16/lb for mediums.
4 Average visual uniformity of fruit shape where 1 = least uniform, 5 = completely uniform.
5 Visual fruit appearance rating where 1 = worst, 9 = best, taking into account overall attractiveness, shape, smoothness, degree of flattening, color, and shape uniformity; all fruits from two replications observed at the first harvest (Aug 9).
6 3&4 = about half and half 3- and 4-lobed; 3 = mostly 3-lobed; 4 = mostly 4-lobed; 2,3,4 = about equal numbers of 2-, 3-, and 4-lobed.

Table 3. Yields from single plots of jalapeno pepper cultivars at Lexington and Quicksand with fruit characteristics from Lexington, Ky., 2001.
Cultivar (resistance gene) Seed source Mkt. yield BLS2 Fruit characteristics Comments
Cracking3 Average4 Appear. rating5 Color6
LEX QSND Ln (in.) Diam (in.) Wt (g)
-- (tons/acre) --
Coyame S 27.4 --1 2 3 3.2 1.3 34 7 mg-dg ~10-20% slightly crescent-shaped
X3R Ixtapa (Bs2) S 26.1 10.4 2 3 3.2 1.3 28 6 mg-dg Some stubby, misshapen (~2%); ~10% purpling
RPP 7042-VP RG 24.9 19.2 2 4 3.3 1.1 25 7 mg
Summer Heat 6000 AC 23.6 19.8 2 3 3.4 1.3 34 7 mg-dg Nice; ~50% very slightly curved
Mitla S 23.4 20.1 3 2.9 1.1 24 7 mg-dg Nice
El Rey (Bs2) SK/SW 23.1 12.9 1 3 3.1 1.3 35 5 mg Taper not always smooth
Torreon S 22.9 20.7 2 3 3.3 1.2 27 6 mg-dg
Ballpark S 21.7 16.2 2 2 3.6 1.0 28 6 mg-dg Some crescent-shaped

(~10-15%)

Grande S 21.4 18.0 4 3 3.2 1.2 30 6 mg ~5% with purple (anthocyanin) areas
HMX 3677 HM 21.3 16.1 2 4 3.0 1.3 26 7 dg
Hybrid No. 7 RU 21.2 22.3 2 2 3.3 1.3 31 6 mg ~10% crescent-shaped
Jalandro UG 20.8 12.2 1 3.3 1.6 40 4 mg
HMX 3676 HM 13.9 16.1 2 3 2.7 1.2 31 7 mg-dg Nice; some frts. very lightly curved.
1 Data not available from Quicksand for this cultivar.
2 Bacterial spot symptoms were observed in some plots at QSND and may have affected yields of those cultivars: '1' = plots with mild infection, '2' = plots with mild to moderate infections, '4' = plots that had severe infections. A blank in this column indicates that no symptoms were observed; blanks or numbers do not imply resistance or tolerance.
3 Extent of cracking in jalapeno fruits where 0 = none; 5 = very extensive, over entire fruit surface (Lexington trial); some cracking may be a desirable trait in Hispanic markets.
4 Average of a sample of 10 fruits (length and width); avg. fruit weight = marketable yields divided by number of fruits (entire season, Lexington).
5 Visual fruit appearance ratings where 1 = worst, 9 = best, taking into account overall attractiveness, shape, color, and uniformity (Lexington).
6 mg = medium green; dg = dark green (Lexington trial).

Table 4. Yields from single plots of specialty pepper cultivars at Lexington and Quicksand with fruit characteristics from Lexington, Ky., 2001.
type

Cultivar

Seed

source

Mkt. yield Bac.

spot2

Fruit characteristics Plant

support6

Comments
LEX QSND Average3 Appear.

rating4

Color5
-- (tons/acre) -- Ln (in.) Diam (in.) Wt

(g)

serrano
Tuxtlas S 22.4 -1 2.9 0.8 12 7 mg req'd. ~20% slightly crescent-shaped
Serrano del Sol S 21.0 17.4 3.1 0.8 11 7 mg req'd. Nice, slightly crescent-shaped
Tampico Fiesta HN/AS 15.3 13.7 2 2.9 0.6 7 6 lg-mg req'd. ~50% slightly crescent-shaped
anaheim
Novajoa S 31.0 23.3 4 8 1.7 65 5 lg-mg ben. ~30% 'C'-shaped
Garden Salsa S 24.6 13.7 2 6.9 1.5 48 6 mg req'd. ~30% 'C'-shaped, many culls from blossom-end decay
Sahuaro S 18.7 12.4 6.7 2.1 73 5 lg req'd. 10-20% 'C'-shaped, many culls from blossom-end decay
PX-35-4606-7 S 18.3 19.6 7.3 2.0 69 7 mg ben. Nice
Anaheim TMR 23 S 17.7 11.7 2 7.0 1.9 59 6 lg req'd. ~20% 'C'-shaped, some blossom end decay
Joe E. Parker R 14.8 21.3 6.3 1.7 59 4 lg req'd. ~40% 'C'-shaped
poblano/ancho
Ancho Villa RG 21.0 12.3 2 5.4 3.0 133 6 lg-mg req'd. Lighter colored than most
SVR 35-4845-7 (Bs2) S 17.2 10.7 4 4.9 2.8 94 7 dg req'd. Very nice
Ancho Ranchero RG 14.6 11.6 2 5.1 2.9 99 4 lg-dg req'd. Highly variable
Ancho San Martin SW 11.4 11.4 4.7 2.7 70 6 mg-dg req'd. Many culls from blossom-end decay
Mulato Costeno S 10.3 10.6 3.9 2.4 67 6 dg req'd. Small fruit size
PS 13194 S 9.7 10.2 1 4.5 2.6 90 6 mg-dg req'd. variable sizes; many culls from blossom-end decay
Mulato Isleno S 3.9 3.9 4.3 2.3 54 5 dg req'd. Small fruit size; very low yield
Italian/cubanelle
Aruba RG 28.3 15.6 1 7.5 3.0 137 5 lg-py ben. ~20% apostrophe-shaped
ACX 500 AC 24.2 9.4 2 7.5 2.8 115 5 py req'd. ~40% apostrophe-shaped; nice color
Corno Di Toro RU 18.4 16.5 4 6.6 2.3 107 6 lg-mg ben. ~10% apostrophe-shaped
Key West (Bs2) S 16.7 22.0 1 7.1 2.9 116 4 lg ben. ~40% apostrophe-shaped
1 Data not available from Quicksand for this cultivar.
2 Bacterial spot symptoms were observed in some plots at QSND and may have affected yields of those cultivars: '1' = plots with mild infection, '2' = plots with mild to moderate infections, '4' = plots that had severe infections. A blank in this column indicates that no symptoms were observed; blanks or numbers do not imply resistance or tolerance.
3 Average of a sample of 10 fruits (length and width); avg. fruit weight based on marketable yields divided by number of fruits (entire season, Lexington).
4 Visual fruit appearance ratings where 1 = worst, 9 = best, taking into account overall attractiveness, shape, color, and uniformity (Lexington).
5 Lg = light green; mg = medium green; dg = dark green; vdg = very dark green; gy = greenish yellow; py = pale yellow; ly = lemon yellow.
6 Staking with one or more strings may be required using double rows on plastic with drip as indicated by 'req'd.' = cultivars requiring staking/support; 'ben.' = cultivars that may benefit from staking.

Table 5. Yields from single plots of specialty pepper cultivars at Lexington and Quicksand with fruit characteristics from Lexington, Ky., 2001.
type

Cultivar

Seed

source

Mkt. yield BLS1 Fruit characteristics Plant

support5

Comments
LEX QSND Average2 Appear.

rating3

Color4
-- (tons/acre) -- Ln (in.) Diam (in.) Wt

(g)

hot banana/wax
X3R Hot Spot (Bs2) S 26.2 23.5 6.3 1.6 54 6 py ben.
Inferno S 25.6 17.7 4 7.0 1.6 64 4 py ben. Over 50% short and apostrophe-shaped
Santa Fe Grande S 16.8 14.5 4 2.9 1.1 19 7 py poss. Very nice; jalapeno size and shape
sweet banana/wax
PX 35-4360-7 (Bs2) S 32.5 26.8 2 6.5 1.6 58 7 py req'd. ~50% 'C'/apostrophe-shaped; many w/ blossom end decay
Market Sweet RU 28.7 15.9 4 6.8 1.8 65 4 py-lg poss. Over 50% short and 'C'/apostrophe-shaped
Sweet Spot S 24.5 17.6 2 6.9 1.8 58 5 py ben. Many culls
Pageant (Bs2) RG 23.6 18.3 6.2 1.7 70 4 py poss. Over 50% short and 'C'/apostrophe-shaped
Banana Supreme RU 23.5 14.9 2 6.2 1.8 65 5 py poss. ~50% short and 'C'/apostrophe-shaped
Bounty S 21.3 20.1 2 7.1 1.6 76 5 py ben. ~50% short and 'C'/apostrophe-shaped
fresno
Grande (upright) PG 7.2 15.0 22 poss.
Supreme (pendant) PG 4.7 3.9 2 19 req'd.
pepperoncini
Pepperoncini RU 17.6 11.5 2 3.9 1.5 39 6 lg-mg req'd. ~40% 'C'-shaped
PX 17494 S 12.5 14.8 1 3.3 1.3 18 7 lg req'd. Mostly straight, more uniform
1 Bacterial spot symptoms were observed in some plots at QSND and may have affected yields of those cultivars: '1' = plots with mild infection, '2' = plots with mild to moderate infections, '4' = plots that had severe infections. A blank in this column indicates that no symptoms were observed; blanks or numbers do not imply resistance or tolerance.
2 Average from a sample of 10 fruits (length and width); avg. fruit weight based on marketable yields divided by number of fruits (entire season, Lexington).
3 Visual fruit appearance ratings where 1 = worst, 9 = best, taking into account overall attractiveness, shape, color, and uniformity (Lexington).
4 Lg = light green; mg = medium green; dg = dark green; vdg = very dark green; gy = greenish yellow; py = pale yellow; ly = lemon yellow.
5 Staking with one or more strings may be required using double rows on plastic with drip as indicated by 'req'd.' = cultivars requiring staking/support; 'ben.' = cultivars that may benefit from staking; 'poss.' = cultivars that possibly need staking under windy conditions or with heavy fruit loads.

Table 6. Tentative ranking of pepper types and cultivars by their relative susceptibility to bacterial spot (based on results from trials at Quicksand, Ky., in 2000).
BLS risk Group1 Resistance gene(s) % BLS22 Cultivars3
Lowest resistant Jalapeños Bs2 3-22 X3R Ixtapa, El Rey
tolerant Serranos -- 3-10 Tampico Fiesta, Serrano Chili
most resistant Bells4 Bs2 8-13 X3R Ironsides, Peninsula, X3R Chalice, X3R Aristotle, X3R Red Knight
resistant Hot banana Bs2 17 X3R Hot Spot
tolerant Habanero -- 22 Habanero (Hollar Seed Co.)
tolerant Cubanelle -- 40 Aruba
tolerant Hot bananas/wax -- 40-52 Hungarian Yellow Wax, ACX 400, Romanian Hot Hybrid
tolerant Cayenne (Misc.) -- 62 Mesilla
tolerant Poblanos/anchos -- 62-67 Ancho San Martin, Ancho Villa
less resistant Bells4 Bs2, -- 63-71 X3R Wizard, Bennington
tolerant Sweet bananas/wax Bs2, -- 62-75 Pageant, Market Sweet, Sweet Banana
susceptible Cubanelles -- 67-77 Biscayne, ACX 500, Giant Aconcagua, Corno di Toro
susceptible Hot bananas/wax -- 65-80 Hungarian Heat, Inferno
susceptible Anaheims -- 72-80 Mexiheim, Garden Salsa, Anaheim TMR 23
susceptible Bells Bs1, Bs35 80-82 King Arthur, Merlin, Consul, Vivaldi, Guardian, Sentinel
susceptible Jalapeños -- 80-87 Mitla, Tam Jalapeño No.1, Delicias, Perfecto, Summer Heat 5000
Highest susceptible Poblanos/anchos -- 72-85 Ancho Ranchero
1 Cultivars within types (Bells, Jalapeños, or hot/specialty types in Tables 4 and 5) grouped as: 1) "resistant" = having Bs2 gene and high yielding with fewer symptoms and defoliation overall than 2) "tolerant" = having no major resistance gene but with considerably fewer symptoms and yielding more marketable fruits than 3) "susceptible" = little to no marketable yield with extensive foliar symptoms and defoliation.
2 % BLS = range of the avg. percentages of leaves with bacterial spot symptoms under severe epidemic conditions at QSND in 2000; data were from 2 assessment dates and one or more cultivars.
3 Not all cultivars tested are listed; others may be equally resistant, tolerant, or susceptible.
4 Bell cultivars that were the "most resistant" with highest yields and gross returns. "Less resistant Bells" are those cultivars (with or without Bs2) that had relatively high AUDPC values, % BLS, and defoliation in 2000.
5 Cultivars having Bs1, Bs3, or both were as susceptible as those with no major resistance genes in 1995 trials.

Plant Populations and Nitrogen Sources for Bell Pepper Production

Thomas J. Brass, Henderson County Cooperative Extension Service, Henderson, Kentucky; Garry Eblen and Barry Eblen, Triple E Farms, Reed, Kentucky; Charles Mulligan, Mulligan Farms, Henderson, Kentucky

Introduction

Commercial pepper production is a fairly new venture for many farmers in the western part of the state where agronomic row crops and tobacco have been the traditional commodities grown. However, the signing of contracts for 100 acres of bell peppers in 2001 through the local co-op gave farmers a chance to grow small acreage pepper plots to determine if higher returns on land, capital, and management could be achieved.

The Kentucky Pepper Integrated Crop Management Grower Manual (IPM-13) was relied upon heavily as our guide for recommended production practices. While those who followed the recommendations in the manual produced high yield and high quality bell pepper crops, there was interest in knowing if growing conditions in this part of the state could support adjustments in pepper stand populations and fertility management practices with the goal of achieving higher economic returns.

Supporting data on optimum bell pepper population stands is not readily available. A 12-inch in-row plant spacing is standard commercial practice that is recommended in the previously mentioned grower manual. This recommendation seems to be supported in part by an experiment by Locascio and Stall (1994) who reported that yields per bell pepper plant were 30 percent greater with a 12-inch in-row spacing than a 6-inch in-row plant spacing; yields per acre were similar with both in-row spacings even though the latter had a 33 percent greater number of plants per acre.

Fertility was another area of interest for reasons that included fertilizer analyses, cost, and application frequency. Two weeks following preplant incorporation of 50 lb N/A, the University of Kentucky recommends that an additional total of 50 to 75 lb N/A from either ammonium nitrate (NH4NO3) or calcium nitrate (CaNO3) be applied in weekly fertigations. Calcium nitrate's per unit cost on an N basis is just more than 4½ times that of ammonium nitrate; however, calcium nitrate's supply of 20 percent calcium was a major reason many producers in the area used this form in hopes of avoiding blossom-end rot since, in contrast to Central Kentucky, base levels of free carbonate are minimal. Furthermore, interest in poultry litter as a fertility source was also evaluated to determine if preplant application could achieve a similar response as that obtained with synthetic fertilizers.

Two separate studies were conducted to evaluate the effects of plant spacing on marketable yield and quality and to determine if differences in fertility management practices would affect pepper yield, quality, and their predisposition to blossom-end rot.

Materials and Methods

Plant Population. The population density study was planted on May 2 using 242-cell trays of bell pepper `Brigadier' transplants. All plants were set on 4-inch high, 3-foot wide beds that were 6 feet between centers and covered with black plastic mulch with drip irrigation. Experimental units consisted of 25-foot-long double rows, 18 inches apart with four different in-row plant spacings. These four treatments included 9-inch, 12-inch, 15-inch, and 18-inch spacings. Preplant fertilizer and weekly fertigation using calcium nitrate was applied as recommended in IPM-13. Treatments were replicated four times in a randomized complete block design.

Plots were harvested four times (weekly from July 2 to July 19 and again on July 26). All peppers were graded into extra large, large, medium, and choppers. Total marketable weight for all harvested peppers was also determined. All data were subjected to an analysis of variance to test for main effects, and a regression analysis was used to determine rate response to pepper plant population treatments.

Poultry Litter and Nitrogen Sources. On May 7, a pepper fertilizer experiment was established with six treatments consisting of a factorial set of three preplant fertilizer combinations of ammonium nitrate (AN) and poultry litter (PL) together with two fertigated nitrogen fertilizers: ammonium nitrate (AN) or calcium nitrate (CN). The preplant fertilizer was applied at 50 lb N/A in combinations that included 100 percent AN, 50 percent AN+50 percent PL, and 100 percent PL. All treatments were applied in fields with transplants and mulch beds similar to those previously described for the population study. Soil pH was 6.2, indicating no additional lime was needed. Each experimental unit consisted of 25-foot-long beds with double rows that were18 inches apart with12 inches between plants in the rows. All treatments were replicated four times and in a randomized complete block design.

Plots were harvested July 7, July 14, and July 24 and graded into extra large, large, medium, and choppers. Total marketable weight for all harvested peppers was determined. The number of peppers with blossom-end rot were counted and pepper greenness was estimated using a qualitative rating scale of 1 to 5 (1 = light green, 5 = darkest green).

Mature leaf samples near the distal end of pepper plants were collected during the second harvest from randomly selected plants from each experimental unit. Collected leaves were analyzed for total nutrient content at Analytical Laboratories, Memphis, Tennessee.

All data were subjected to an analysis of variance to test for main effects, and the orthogonal polynomial trend comparisons procedure was used to evaluate the effect of preplant fertilizer combinations and fertigation N source.

Results and Discussion

Plant Population. Yield and weight measurements for all treatments showed a similar general response to differences in pepper population density and time of harvest. On a per plant basis, 15-inch and 18-inch spacings tended to have consistently higher weights (Figure 1) and more extra-large peppers (Figure 2) compared to 9-inch and 12-inch spacings, although higher per acre marketable yields and numbers of extra-large peppers were generally achieved with the 12-inch and 15-inch spacings. The one exception to this was after the fourth harvest: the 18-inch spacing was significantly higher in pepper weight and extra-large grade peppers.

Peppers graded large showed the highest yields for 9- through 15-inch spacings during the first and second pickings on a per acre basis. However, the third and fourth harvest had higher large-graded pepper yields for spacings between 12 and 18 inches. On a per plant basis, a 15-inch spacing produced a higher number of large-grade peppers for the first two pickings, while the 18-inch spacing produced a greater number of large-grade peppers for the final two pickings when compared to other treatments. The 9-inch spacing averaged 20 percent lower large-grade yields on a per plant basis regardless of the time of harvest. Overall, the number of chopper-grade peppers stayed around 30 percent of total harvest regardless of plant spacing.

Total yield (Table 1) did not differ on a per acre basis for any of the spacings. Spacing peppers at 9 inches, however, did produce less total weight (Table 1) when compared to the other treatments.

Information from these studies should not be considered recommendations for commercial bell pepper production. Rather, this information can be used to help make appropriate adjustments to individual operations. Data from the population density study indicate that spacing plants at 12 or 15 inches tended to result in higher pepper yields and weights through the first half of the harvest season. Eighteen-inch spacings resulted in higher yields during the second half of the harvest season.

While high yield potential is possible with 18-inch spacings during the latter part of the growing season, several disadvantages come to mind if using this spacing: target market date, inefficient water usage, and increased potential for sunburned fruit.

Premium prices for Kentucky-grown peppers generally occur during the first half of July. Peppers spaced 18 inches apart may miss this window of maximum profit potential as seen with 12 and 15 inches and the premium prices they might receive.

Poultry Litter and N Sources. There were no significant differences for any of the growth and yield measurements among the different preplant treatments of poultry litter, ammonium nitrate, or the combination of the two, nor were there interactions with the two different N fertilizer types used for supplemental fertigation (data not shown). Using poultry litter as the sole source of preplant fertilizer, or in combination with ammonium nitrate, resulted in similar plant growth and yield.

Fertigation with ammonium nitrate resulted in a higher number of extra-large peppers than fertigation with calcium nitrate (8.3 from AN vs. 5.1 from CN) during the first picking and for the total number of extra-large peppers harvested (Table 2) prior to the experiment's termination. In addition, harvested peppers tended to be darker green (Table 2) than those grown solely under fertigation with calcium nitrate.

The number of large-, medium- and chopper-grade peppers were similar in number for each harvest interval (data not shown) and for their respective totals (Table 2) regardless of fertilizer N type. Using ammonium nitrate as the sole fertilizer source for fertigation did not produce a higher number of peppers with blossom-end rot. Neither treatment resulted in fruits affected by blossom-end rot in this trial.

Leaf analyses of pepper plants indicated that fertigation N type had a significant effect on leaf N content; however, N leaf content was also affected by a preplant N type x fertigation N type interaction (Table 3). Pepper N leaf content was higher in plants under ammonium nitrate fertigation. No differences in other essential elements, including leaf calcium content, were present for any of the treatments evaluated (data not shown).

Peppers responded well to poultry litter used as a preplant fertilizer source. Fertigation with ammonium nitrate produced more extra-large peppers, resulted in a higher foliar N content, and darker green pepper plants than did fertigation with calcium nitrate. One inference as to why ammonium nitrate produced more extra-large peppers, with a slightly darker green color, is the higher nitrogen content within the plant. No differences were found, however, for the number of large, medium, and chopper-grade peppers, as well as total yield and weight between ammonium nitrate or calcium nitrate fertigation.

This study also suggests that if pH is corrected prior to planting, ammonium nitrate may be used as the sole fertigation N source without causing an increase in blossom-end rot. This is also supported by the fact the leaf Ca content was similar for both ammonium nitrate and calcium nitrate fertigation. The key to preventing blossom-end rot seems not to be the influx of available calcium but rather keeping moisture consistent within a plant's effective root zone during the growing season. This is best accomplished by using plastic mulch and drip irrigation with irrigation frequency determined by routine soil moisture monitoring with tensiometers.

One option not evaluated in this study that growers may want to consider if they are concerned about calcium availability is alternating between ammonium nitrate and calcium nitrate for weekly fertigations.

Literature Cited

Locascio, S.J., and W.M. Stall. 1994. Bell pepper yield as influenced by plant spacing and row arrangement. J. Amer. Soc. Hortic. Sci. 119:899-902.

Figure 1. Pepper harvest weights on a land unit basis.

Figure 2. Extra-large grade peppers on a land unit basis.

Table 1. In-row spacings' influence on total harvested bell pepper weight and yield on a per plot basis, Henderson County, Ky., 2001.
In-row plant spacing Total

weight

(lb/plot)

Total

X-Large1

(no./plot)

Total

Large

(no./plot)

Total

Medium

(no./plot)

Total

Chopper

(no./plot)

Total

peppers

(no./plot)

9 inch 103.5 b2 78.2 68.0 8.3 65.8 220.3
12 inch 127.7 a 84.2 72.5 7.2 76.5 240.4
15 inch 121.0 a 79.3 69.4 5.8 81.2 235.7
18 inch 118.3 a 84.8 73.2 3.0 64.2 225.2
NS3 NS3 L3 NS3
1 Pepper grades: Extra-large (>7 oz); Large (6-7 oz); Medium (<6 oz); Choppers (deformed fruit).
2 Means followed by same letter do not significantly differ within columns (P = 0.05, Duncan's MRT).
3 L = significant linear response. NS = non significant; * = significant at P 0.05.

Table 2. Fertigated N type's affect on bell pepper weight, yield and fruit characteristics, Henderson County, Ky.
Fertigated

N Source

Total

X-Large1

(no./plot)

Total

Large

(no./plot)

Total

Medium

(no./plot)

Total

Chopper

(no./plot)

Total

peppers

(no./plot)

Fruit

color2

(1 - 5)

Ammonium Nitrate 66.0 a 3 42.1 11.6 46.1 165.8 3.8
Calcium Nitrate 55.8 b 38.5 9.4 43.4 147.1 3.3
NS NS NS NS NS
1 Pepper grades: Extra-large (>7 oz); Large (6-7 oz); Medium (<6 oz); Choppers (deformed fruit).
2 Fruit color: 1 = lightest green, 5 = darkest green.
3 Means followed by same letter do not significantly differ within columns (P = 0.05, Duncan's MRT).

Table 3. Preplant and fertigated N type's affect on pepper leaf total percent nitrogen content at second harvest, Henderson County, Ky., 2001.
Fertigated N Source Preplant fertilizer treatment
100% AN 50% PL+

50% AN

100% PL
% N
Ammonium Nitrate 5.1 a 1 5.2a 5.2 a
Calcium Nitrate 4.8 b 4.5 b 4.8 b
1 Means followed by same letter within columns are not significantly different (P0.05).

Feasibility of Biological Control of European Corn Borer in Peppers

April Satanek, Brent Rowell, and Ric Bessin, Departments of Horticulture and Plant Pathology

Introduction

Integrated pest management practices have aided farmers in reducing the amount of pesticides used to control insects and in using them more effectively when needed. Biological control is a component of IPM that is growing in popularity, especially among organic growers. Biocontrol uses one living organism to control the population of an unwanted pest. Tiny parasitic wasps (less than 0.5 mm long) from the genus Trichogramma have been used as biocontrol agents in sweet corn against European corn borer (ECB), Ostrinia nubilalis. ECB is also the most serious insect pest in peppers in Kentucky. Pepper crops are often damaged by second and third generation ECB larvae in the middle to later part of the growing season. Once hatched, the larvae are difficult to control because they quickly tunnel into the caps of pepper fruits. Once inside the fruit, ECB larvae cannot be killed with insecticides. Subsequent injury may go undetected until fruits decay from bacterial soft rot that occurs as a result of ECB damage.

Trichogrammae ostriniae is an egg parasite that was introduced into the United States from China. This species has been tested and found effective in reducing the number of insecticide treatments for control of ECB in sweet corn in the Northeast. Little is known about the wasps' effectiveness in controlling ECB in peppers, and to our knowledge this species has not been previously evaluated for its effectiveness in peppers. In this preliminary trial, we released T. ostriniae in a small, unreplicated trial in order to get an idea of its potential for ECB control in bell peppers and to learn scouting and other procedures in order to better plan replicated trials for 2002.

Materials and Methods

Two bacterial spot-resistant bell pepper cultivars, `Early Sunsation' and `Defiance', were planted in each of two 50-foot by 50-foot plots that were prepared at separate sites at the University of Kentucky Horticultural Research Farm in Lexington. One of these identical plots was designated the release plot and the other the control plot (no T. ostriniae released). The plots were approximately 300 yards apart, with fields of other crops, a gravel parking lot, and a building between them. The release plot was located downwind from the control plot.

Peppers were seeded on April 19 and transferred to 72-cell trays on May 16. The plants were set on May 30 into raised beds with black plastic mulch and drip irrigation. Standard commercial practices were used: plants were grown in double rows with 12 inches between plants within the row and 15 inches between the double rows. Each plot consisted of six double-row beds (384 plants) bordered by guard rows on each side (128 plants). The plants were irrigated as needed based on tensiometer readings.

One hundred and fifty pounds per acre of ammonium nitrate (50 lb N/A) was incorporated into each plot prior to planting. Plots were fertilized with P and K according to soil test results. An additional 10 lb N/A as ammonium nitrate was applied in the release plot and 7 lb N/A in the control plot in three fertigations. Total season N applications including preplant were 60 lb N/A for the release plot and 57 lb/A for the control plot. Maneb and copper (TennCop) were applied weekly to both plots to protect against bacterial spot. The insecticide Spintor was mistakenly applied once in the control plot; no other insecticide treatments were applied in the control or release plot. A pheromone trap was placed adjacent to the release plot to monitor ECB activity.

Thirty thousand T. ostriniae-parasitized Ephestia eggs (glued inside two paper cups with 15,000 each) were obtained from Cornell University and placed in the release plot on July 11. This was the date predicted as the first flight of second generation ECB moths for Lexington by the University of Kentucky ECB degree-day model. That flight turned out to be very light, and we decided to obtain and release a second batch of 30,000 a week later on July 18 in the same field. Paper cups containing the egg parasites had been folded and stapled shut in order to protect against predators and exposure; numerous pinholes had been made in the cups to allow the parasites to emerge. Releases were simply a matter of hanging the two paper cups under the leaf canopy of a plant in the center of the plot.

Plots were scouted twice weekly and the number of parasitized and unparasitized ECB egg masses recorded. Once eggs were located and their status recorded, leaves with eggs were flagged with a plastic marking ribbon and given a number. These egg masses were visited twice weekly and their condition recorded until hatching or their disappearance.

All green mature fruits were harvested on August 1 and 18. Marketable fruits were graded and weighed according to size class (U.S. No. 1 extra large, large, medium). Each fruit was carefully examined for signs of ECB feeding or injury; all fruits with noticeable signs of ECB activity were dissected to determine the presence of larvae. Only fruits with one or more larvae inside were recorded as having ECB damage.

Results and Discussion

ECB egg masses were first discovered in the trial on July 13. The second generation ECB moth flight was not as concentrated as in past years, and only small numbers of moths were caught until the end of the season. Our plan had been to release T. ostriniae to coincide with the predicted flight of second generation ECB around July 10; however, a total of only seven ECB moths had been trapped by July 25. The detected initiation of the moth flight occurred about a week later than predicted. This may have been due to low ECB numbers. A total of 19 egg masses in the release plot were located and monitored until hatching or disappearance from July 13 until August 10.

Only three ECB egg masses were found in the control plot; however, more than double the number and weight of ECB-damaged fruits occurred in this plot than in the release plot (see table below). The release plot yields were slightly higher than control plot yields. It is not known why ECB masses in the control plot were not as easily detected as those in the release plot. Many T. ostriniae-parasitized ECB egg masses were also found in an adjacent sweet corn trial after ECB egg numbers in the pepper plot had declined. Only a few very small clusters of one to three ECB eggs were found in the pepper plots toward the end of the growing season.

Many of the flagged egg masses, whether parasitized or not, seemed to disappear during the course of the trial. These disappearances might have been caused by the feeding of predatory insects such as lady beetles, by egg casings being eaten after ECB or wasp emergence, or simply by becoming detached and lost.

Notes on scouting. Scouting techniques included brushing pepper leaves up with one's arm to expose undersides of the leaves. ECB eggs were most often found half way up from the bottom of the plant on the undersides of leaves and fruit. ECB moths laid eggs indiscriminately on both hail-damaged and whole leaves alike. Viable ECB eggs are scale-like, circular, milky-white with an iridescent casing; they are deposited in clusters (masses). When T. ostriniae parasitizes a ECB egg, the inside of the egg turns solid black. This parasitized condition should not be confused with the "black head" stage of ECB eggs. The black head stage occurs in non-parasitized eggs when heads of the ECB larvae become visible about 24 hours prior to hatching. The black head stage is not as completely black as in parasitized eggs. T. ostriniae are not able to parasitize eggs in the black head stage. Adult female T. ostriniae lay their eggs in ECB eggs, sometimes depositing more than one egg in each ECB egg. The wasp larva hatches inside the ECB egg, feeds on the contents, and pupates. The adult wasp chews a circular escape hole in the ECB egg casing and vacates the egg. These escape holes were visible with a hand lens. It takes about 10 days from egg deposition to wasp emergence. Because of their extremely small size, there appears to be no other practical way of monitoring T. ostriniae activity other than locating and recording parasitized eggs.

Many environmental factors are known to affect the success of T. ostriniae. The wasps prefer temperatures between 62 and 89°F, and relative humidities between 45 percent and 95 percent. The adults probably feed on nectar of the pepper plant flowers. Strong winds, dust, and rain will affect the wasps' performance. Studies conducted by Cornell University in New York have shown that T. ostriniae can persist even when pesticides are used because the developing wasps are protected inside the ECB egg.

Further trials. It was not our intention to determine if T. ostriniae could successfully control ECB in peppers in this preliminary trial. We hoped that these observations might indicate whether the technique looked promising. The results do seem to suggest that one or two inoculative releases of T. ostriniae have potential to help control ECB in peppers. The test also provided insights on scouting procedures and data collection for use in future trials.

Acknowledgments

Our thanks to Larry Blandford, Spencer Helsabeck, John Holden, Dave Lowry, Bonnie McCaffrey, and Kirk Ranta for help with harvest and data collection. We would also like to gratefully acknowledge the assistance of Mike Hoffmann, Mark Wright, and Sylvie Chenus of the Department of Entomology at Cornell University for generously providing the parasites and for their helpful suggestions and advice.

Note: see <www.uky.edu/Ag/Entomology/entfacts/fldcrops /ef106.htm> for more information regarding the degree-day model for predicting flights of European corn borer in Kentucky.

European corn borer damage and pepper yields in T. ostriniae release and control plots at Lexington, Ky., 2001. Data are season totals from two harvests.
ECB-damaged fruits Mkt. yields (lb/plot) Culls (lb/plot)
no./plot wt (lb/plot) X-Large Large Med. Total
T. ostriniae release 35 16 729 143 13 885 46
control 74 38 580 206 8 794 30

Yields and Quality of New Muskmelon Cultivars in Central Kentucky

Brent Rowell, April Satanek, and John C. Snyder, Department of Horticulture

Introduction

Muskmelons or cantaloupes are one of the most important commercial vegetables in the region and are a priority crop for the UK vegetable research and Extension team. Muskmelons are the primary crop being grown and marketed by the newly formed Green River Produce Marketing Cooperative based in Hart County. This co-op serves small farmers in one of the most tobacco-dependent areas in the state. A few new eastern-type muskmelon cultivars have been recently released, some of which claim to be similar to Athena, which is currently the market standard. In this trial we compared three new cultivars with Athena.

Materials and Methods

Two seeds were sown into each cell in plastic cell packs (72 cells/tray) on 26 April at the UK Horticulture Research Farm in Lexington; trays were placed on bottom heat in a heated greenhouse until germination. Once germinated, the plants were moved to a cooler greenhouse. Plants were set in the field on 30 May into raised beds covered with black plastic with drip irrigation. The two plants from each cell were transplanted 3 feet apart within the row (two plants/hill) with 6 feet between rows. Plots consisted of two adjacent rows with five hills (10 plants) each in a randomized complete block design with four replications.

The plots were fertilized prior to planting with 150 lb/A of ammonium nitrate (50 lb N/A) and with P and K according to soil test results. An additional 30 lb/A (10 lb N/A) of ammonium nitrate was fertigated twice during the growing season for a season-long total of 70 lb N/acre. Curbit was applied for weed control between rows of plastic prior to vine coverage. The systemic insecticide Admire 2F was applied to the base of each plant soon after transplanting, using a backpack sprayer with the nozzle removed. Other insecticides were used as needed later in the season. Either Bravo or Quadris was applied on a weekly basis for disease control. Plots were scouted twice weekly to monitor pests and diseases. Plots were harvested six times between 6 August and 24 August. Measurements and soluble solids were determined on a subsample of five fruits from each variety in each replication from the first three harvests (6, 9, and 13 August).

Results

Cucumber beetle populations were high early in the season; many beetles were observed on transplants as they were set out. The post-transplant drench treatment with Admire was very effective for early season beetle control; vine coverage was early and thick. Plants were harvested six times, when fruit were at full slip.

Due to cloudy, rainy weather early in the season, the first harvest yielded mostly bland, low sugar fruit. Although there were no statistically significant differences for season-long yields, Minerva was the highest yielding in terms of tons of fruit per acre (Table 1). This variety had large fruits with deep sutures and heavy netting; it also had the highest soluble solids (sugar content) and was rated best for taste among the varieties tested (Table 2). Average fruit size was similar for Minerva, Odyssey, and Vienna (around 7 to 8 lb); all were larger than Athena (5 to 6 lb). Athena had the largest number of marketable fruits among the four cultivars (more than 10,000 per acre). Although none of these average sugar contents met USDA requirements for the "U.S. Fancy" grade, Minerva and Odyssey met the U.S. No. 1 grade. Higher sugar contents would be expected in a drier season.

Fruits of Odyssey were oblong and lightly netted. Odyssey looked much like Athena, although Odyssey fruits had deeper sutures. Athena yielded the most melons per acre, although sugars were low compared to Minerva and Odyssey. Vienna was also considered acceptable, although without outstanding qualities compared to the other cultivars in this trial. It will be difficult for new cultivars to compete when wholesale buyers continue to request Athena. For the time being, Minerva will be recommended for farmers' field trials as an excellent melon for roadside and local sales.

Acknowledgment

The authors would especially like to thank Darrell Slone, Janet Pfeiffer, Dave Lowry, Bonnie McCaffrey, Larry Blandford, Spencer Helsabeck, and John Holden for their hard work and generous assistance with these trials.

Table 1. Average yields and fruit size for muskmelon cultivars, Lexington, Ky., 2001; data are means of four replications from six harvests.
Cultivar Seed source Reported disease tolerance1 Days to harvest Yield

(cwt/A)

Yield (tons/A) Mkt. fruit no./A No. culls/A Average fruit size (lb)
Minerva RG F0,1,2; PM1,2 77 673 33.7 8833 303 7.6
Odyssey SS F1,2; PM 75 585 29.2 7925 786 7.4
Athena RG F0,1,2; PM1,2 80 556 27.8 10285 1089 5.4
Vienna S 80 549 27.4 7381 726 7.4
1 F = Fusarium; PM = Powdery mildew; subscripts indicate races of the pathogen to which the cultivar is resistant or tolerant.

Table 2. Fruit quality characteristics of muskmelon cultivars, Lexington, Ky., 2001; data are means from a subsample of five fruits in each replication from the first three harvests.
Cultivar Seed source Fruit size Cavity size Flesh thick. (in.) Taste1 S. solids

(%)

Shape2 Netting3 Sutures4 Comments
Ln (in.) Diam. (in.) Ln

(in.)

Diam.

(in.)

Minerva RG 8.0 7.4 5.5 3.5 2.3 3.5 10.6 Rnd-Obl Hv Dp Very deep sutures.
Odyssey SS 8.6 6.9 6.0 3.3 2.0 2 10.0 Obl Lt-Md Md Blossom-end scars
Athena RG 7.9 6.7 5.0 2.8 1.9 2 8.3 Rnd-Obl Md Sh Smaller fruits
Vienna S 8.5 7.5 5.6 3.3 2.1 2 8.0 Obl Md Sh Nice flesh color.
1 Informal taste rating scale: 1 = unpleasant texture, bland; 5 = excellent, very sweet muskmelon taste.
2 Shape: Rnd = round, Obl = oblong.
3 Netting: Lt = light, Md = medium, Hv = heavy.
4 Sutures: Sh = shallow, Md = medium depth, Dp = deep.

Yields and Quality of New Muskmelon Cultivars in Eastern Kentucky

William Turner, Amanda Ferguson, and R. Terry Jones, Department of Horticulture, University of Kentucky Robinson Station

Eastern muskmelon (cantaloupe) production has been identified as one of several profitable crops that Kentucky farmers can produce. Potential yields of 8,000 to 10,000 fruit/acre with gross returns of $5,000/acre are possible. Variable costs are roughly $1,000 per acre, and net returns to the grower are in the $2,200 range.

One farm cooperative, several grower marketing associations, and numerous farmers' market producers are currently producing cantaloupes for fresh market sales. This cultivar trial compares Athena, which is currently produced on 75 percent of all Eastern cantaloupe acreage, with five other cultivars that produce similar fruit. The cultivars were compared as to yield, fruit quality, and consumer acceptance.

Methods

Six cantaloupe cultivars (Table 1) were compared to determine yield, quality, size, percent solids, and shipping quality for potential use by Kentucky cooperatives for wholesale trade. An evaluation of taste, smell, and appearance was also made.

Cantaloupe seeds were seeded in plug trays and grown in the greenhouse for three weeks before transplanting on June 12. Cultivars were replicated four times with five plants per plot (3 feet between plants) in a randomized complete block design. Each replication was 15 feet long with rows that were 7 feet from center to center. Soil test results are shown in Table 2.

We applied 50 lb/acre actual N and 100 lb/acre K2O fertilizer preplant. An additional 50 lb actual N in the form of ammonium nitrate fertilizer was applied through the drip irrigation system. Curbit 3E and Gramoxone Extra (2.5) at 4 pints and 2 pints respectively were used for weed control between the plastic mulch strips two weeks after transplanting. One application of Poast 1.5 E at 2 pints/acre was applied as a spot treatment later in the season for control of annual grasses. Insect and disease controls were applied as needed.

Results

There was a significant difference in average fruit number per acre and average fruit size (Table 3). There was no statistically significant difference among cultivars in pounds of fruit produced per acre. Athena produced significantly more fruit per acre than Vienna or Minerva but was not different from the other three melons. Athena also produced fruit that were significantly smaller than the other five cultivars. In roadside sales at a local fruit stand, customers chose (based on appearance) Minerva first, followed by Eclipse and RAL- 8793VP. When not displayed at the same time, Athena also sold well. Vienna and Odyssey did not sell well. In a taste and appearance rating using cut melon cubes, Athena, Minerva, and Eclipse were all rated highly by the participants. No one liked Vienna; Odyssey was not tested. At roadside stands, Eclipse, Minerva, and RAL 8793 VP would receive premium prices. Yield and fruit quality still make Athena the melon to beat for wholesale markets. Additional tests are planned for next year.

Table 1. Muskmelon cultivars tested at Quicksand, Ky., 2001.
Cultivars Days to Mat* Seed

Source

Comments
Eclipse 63 SW large size, good quality
Odyssey 65 SS heavy netted, shallow sutures, holds and ships well.
Vienna 63 SW (S) medium shelf life,
RAL 8793-VP 63 SW (RG) large, very attractive, similar to Minerva.
Athena 63 SW (RG) firm flesh, good shipper.
Minerva 65 SW (RG) large, very attractive fruit
* Days from transplanting to first fruit harvested.

Table 2. Soil test results for muskmelon trial field at Quicksand, Ky., 2001.
pH P K Ca Mg Zn
6.3 132 335 5167 254 15.5

Table 3. Yields and quality of muskmelon cultivars at Quicksand, Ky., 2001; data are means of 4 replications.
Cultivar Avg wt/

fruit1 (lb)

Fruit/A1 Pounds/A Rind thickness (mm) % Soluble solids Comments (shape and appearance)
Eclipse 8.8 a 5,601 ab 49,036 7.0 11.5 nice
Odyssey 8.8 a 6,016 ab 53,039 - 9.0 nice, elongated
Vienna 9.0 a 5,083 b 46,230 - 8.6 nice, plts showed MO deficiency
RAL 8793VP 8.7 a 5,601 ab 48,735 - 10.2 nice, good flesh color
Athena 6.4 b 6,846 a 43,440 2.6 8.8 small looking
Minerva 9.7 a 4,771 b 45,349 3.4 13.5 nice, melon chosen by customers first
LSD (P = 0.05) 1.5 1,636 ns
1 Means followed by the same letter are not significantly different.

Table 4. Informal muskmelon taste test results at Quicksand, Ky., 2001; data are averages from six tasters using a scale of 1-10 (1 = poor and 10 = excellent).
Cultivar Smell Taste Texture Comments
Eclipse 5.0 6.2 7.2 Pretty looking, very good taste.
Odyssey* na na na na
Vienna 3.8 1.0 4.8 Poor, no taste or smell
RAL 8793-VP 5.7 6.8 5.8 Sweet, good taste
Athena 6.3 6.0 6.8 Good taste
Minerva 6.0 5.3 6.3 Good smooth taste
* Odyssey was not available at the time of the evaluation.

Specialty Melon Variety Observation Trial

John Strang, April Satanek, R. Terry Jones, Ric Bessin, Dave Lowry, Bonnie McCaffrey, Spencer Helsabeck,
and John Holden, Department of Horticulture

Introduction

In this trial, a number of specialty melon varieties were evaluated in single (non-replicated) plots: honeydew, honeydew/cantaloupe hybrid, casaba, Christmas, canary, charentais, ananas, and others. These melon varieties vary considerably in taste, color, and size. All are very susceptible to bacterial wilt, making them very difficult to grow in Kentucky. The primary objective of this study was to see if these varieties could be grown using the newly approved soil insecticide Admire 2F for cucumber beetle and bacterial wilt control. These melons have the potential to become a high quality specialty item for local markets. This preliminary trial was not replicated since it was meant to eliminate poor cultivars and to identify promising cultivars worthy of further investigation.

Materials and Methods

Seeds of 20 specialty melon cultivars were planted in cell packs (72 cells per tray) on April 24 and May 10 in a greenhouse at the Horticulture Research Farm in Lexington; cell packs were set on a mist bench with bottom heat for germination. After germination, seedlings were thinned to one plant per cell and moved to a drier, cooler location. Plants were set into black plastic mulched, raised beds using a waterwheel setter on May 17 and May 29. Each plot was 45 feet long with 15 plants set 3 feet apart within the row. Rows were 6 feet apart. Drip irrigation was used to provide water as needed based on tensiometer readings.

One hundred and fifty lb/A of ammonium nitrate (50 lb N/acre) was applied and incorporated prior to planting. The plot was fertigated with a total of 13 lb N/A as ammonium nitrate divided into two applications. The systemic insecticide Admire 2F was applied to the base of each plant immediately after setting, using the maximum rate of 24 fluid ounces per acre. Foliar insecticide and miticide applications during the season included Sevin, Pounce, Asana, and Kelthane. Fungicide applications included Bravo and Quadris. Plots were scouted twice a week to determine the need for pesticide applications. A preemergence herbicide application of Curbit was applied and incorporated between the rows, just as vines began to cover the plastic.

Results

The use of Admire at the high rate resulted in very little plant loss despite extremely high early season cucumber beetle populations. Admire made it possible to grow some types of highly susceptible specialty melons in Kentucky. The 2001 growing season was not abnormally wet, although significant amounts of rain occurred early in the season. As a result, the first melon harvest produced many decayed fruit and resulted in low melon sugar contents (Table 1). Later harvests, as the weather turned drier, had improved yields, appearance, and sugar contents. Some melons did not "slip" at maturity (honeydew/cantaloupe hybrids) and were difficult to harvest at the correct stage. Some varieties cracked, split, and decayed and were judged as not being acceptable for production in Kentucky. Although early vine coverage was full and lush, anthracnose became a problem later in the season.

Honeydew type. The best overall honeydew type melons were Honey Brew, Sundew, and Honey Gold. Honey Brew was judged to be the best honeydew melon in the trial due to its exceptional flavor and large fruit size (Table 1). Sundew was a high yielding variety, with a high sugar content and good disease tolerance/plant survival. Honey Gold had good plant survival in the field and had light orange flesh with a green rind (Table 2) and was judged worthy of further trial. All of the honeydew type melons showed surface checking (Table 2). Creme de Menthe was the highest yielding honeydew, but the distinctive, slight mint flavor was not universally acceptable to our tasters. Earli Brew, an early maturing honeydew type, cracked severely, and the plants succumbed to disease quite early.

Canary (San Juan Canary) type. Dorado was one of the best melons in this category and in the trial. It was an attractive gold color and had a high yield with an excellent taste and few culls. Sonora also yielded well, despite increased disease incidence; however, this variety showed skin checking and was not as attractive externally as Dorado. Mary Gold, a casaba type melon, is smaller and rounder than canary melons but is often sold as a canary melon. It did not have the quality of the other two.

Miscellaneous melon recommendations. St. Nick, a long storage melon, produces over a long period and had a high sugar content with crispy, tasty flesh. HSR 2528 is an ananas type melon that matures late. When ripe, it has an excellent aroma and sweet flavor and is a heavy, dense melon. None of the charentais type melons performed well, and they were judged unacceptable for field production in Kentucky. They showed severe cracking and disease problems and had a bland taste under wet weather conditions. However, local chefs raved about the quality of French Orange. Sun Jewel, an Asian melon, is not a melon in the American sense as its taste is more reminiscent of cucumbers.

Table 1. Specialty melon fruit characteristics from single plots at Lexington, Ky., 2001.
Variety Seed

source

Days

to

harvest

Yield

(cwt/A)

Culls

(No./A)

Avg.

wt/fruit

(lb)

Exterior Fruit Flesh

thick.

(in.)

Seed cavity Disease

incidence

(%)1

Sugar

(%)

Flavor

(1-5)2

length

(in.)

width

(in.)

length

(in.)

width

(in.)

Creme de Menthe SS 82 556 2,097 6.5 9.0 7.6 1.7 6.0 4.2 15 11.8 3.5
Sundew SS 85 554 1,613 5.9 8.1 7.3 1.9 5.1 3.7 5 12.6 3.9
Honey Brew RU 90 453 3,387 8.3 9.2 7.5 1.9 6.0 3.9 20 14.2 4.5
Sonora RU 90 425 1,613 4.7 7.7 6.5 1.8 4.5 3.1 35 11.8 4.3
Dorado SW 85 414 323 5.6 8.6 6.8 1.9 5.2 3.0 15* 13.5 4.8
Honey Gold HM 85 414 323 6.1 7.8 6.9 1.7 5.1 3.4 5 13.4 3.9
St. Nick HR 84 344 323 8.5 10.5 7.4 1.9 7.4 3.6 10 13.0 4.5
Passport HL/RU 75 327 2,742 4.3 7.0 6.7 2.0 3.8 2.7 50* 8.8 2.8
Mary Gold RU 92 308 161 3.4 7.0 5.7 1.6 4.5 2.5 20 12.6 3.5
HSR 2528 HL 95 288 484 3.8 8.7 6.2 1.6 5.9 3.1 5 11.8 4.5
Sun Jewel JS 68 269 2,097 1.6 7.4 3.7 1.0 5.8 1.9 10 12.5 2.0
Gallicum HR 80 257 5,162 3.9 6.2 6.0 1.8 3.9 2.5 15* 13.4 3.5
HMX0580 HM 80 237 3,065 5.4 8.0 6.0 1.7 5.1 2.6 20* 11.7 3.0
HSR 2527 HL 75 231 3,549 4.1 6.6 6.4 1.6 4.0 3.1 40 10.4 3.3
HMX 9606 HM 85 169 2,581 2.4 5.3 5.1 1.5 3.6 2.3 5 12.9 3.0
Earli Brew SW 93 160 2,097 4.0 7.5 7.0 1.8 4.9 3.4 70 9.8 3.1
French Orange HR 75 132 10,162 2.2 5.0 4.6 1.4 3.0 1.9 30 13.0 3.8
Early Hybrid Crenshaw BU/SW 90 120 2,258 4.7 8.2 7.2 1.9 5.0 3.5 75 11.3 3.9
Dove HL 75 104 4,839 4.3 7.1 6.0 1.8 4.4 2.5 30 14.8 4.0
Alienor RU 80 53 4,194 2.8 5.7 5.2 1.4 3.9 2.5 80 7.3 2.0
1 Estimated percentage of plant affected by anthracnose.
* Bacterial wilt disease also found.
2 1 = poor, 5 = excellent sweet taste, pleasant texture.

Table 2. Specialty melon fruit and vine characteristics from single plots at Lexington, Ky., 2001
Variety Melon

Type1

Flesh

Color2

Rind

Color3

Fruit

Shape4

Cracking

(1-4)5

Net

Type6

Comments
Creme de Menthe HD lg - mg lt gr Ov 2.0 na Doesn't slip, fruit checks with maturity, variable palatability, vines look good.
Sundew HD lg - mg lt gr Ov 2.0 na Doesn't slip, fruit looks good, surface checking, and yellowing, fuzzy exterior.
Honey Brew HD lg - dg lt gr Ov 2.0 na Doesn't slip, skin checking when ripe, fuzzy fruit, vines held up
Sonora CA cr - lg dk yl Ob 2.0 lt Doesn't slip, bright yellow exterior, surface checking, vines held up well.
Dorado CA cr - lg dk yl Ob 1.0 lt Doesn't slip, bright yellow exterior, excellent quality fruit, highly rated by local chefs vines look good, chefs, vines did not hold up.
Honey Gold HD lo lt gr Ov 1.0 na Doesn't slip, thick green rind, firm, crunchy flesh, excellent vines.
St. Nick CR cr - wh dk gr w/ lt gr

streaks

Ob 1.0 md Doesn't slip crisp flesh, produces over a long period, vines held up well, pick immature for better storage.
Passport GA lg - mg tn/yl Ro 4.0 hv Stem slips when ripe, many fruit split open, vines held up medium, severe anthracnose.
Mary Gold CS lg - cr dk yl Ro 1.0 lt Doesn't slip, wrinkly exterior, vines look good.
HSR 2528 AN cr - gr cr/yl Ob 1.5 hv Stem slips when ripe, heavy, dense melon, excellent quality.
Sun Jewel AS wh - cr md yl w/wh

sutures

Ob 4.0 na Stem slips when ripe, fruit taste more like cucumbers and crack severely, produces over long time, vines very disease resistant.
Gallicum GA lg tn/yl Ro 2.5 hv Stem slips when ripe, vines look good.
HMX0580 CA cr - or dk yl Ob 2.0 lt Doesn't slip, some chlorosis in leaves.
HSR 2527 AN cr tn/yl Ro 1.5 hv Stem slips when ripe, a lot of variation is fruit size, severe anthracnose.
HMX 9606 CH do tn/yl w/gr sutures Ro 2.5 md Harvest at half slip, melon firm to cut, thin rind, difficult to tell when ripe.
Earli Brew HD lg/cr lt gr Ro 2.0 na Doesn't slip, attractive interior, plants lost to anthracnose.
French Orange CH do tn/yl w/gr

sutures

Ro 4.0 hv Pick at half slip, firm, high quality, deep orange flesh, highly rated by local chefs, fruit splits in wet weather.
Early Hyb. Crenshaw CN mo lt gr Ro 3.0 na Doesn't slip, lost a lot to decay in wet weather, lost about the vines.
Dove AN lo - lg tn/yl Ob 4.0 md Stem slips when ripe, lost majority of fruit to disease.
Alienor CH mo tn/yl w/gr

sutures

Ro 4.0 lt Stem slips when ripe, fruit cracks open and decays before ripening in wet weather, vines did not hold up.
1 Melon Type HD = honeydew, CA = canary, CR = Christmas, GA = galia, CS = casaba, AN = ananas, AS = Asian, CH = charentais, CN = crenshaw
2 lg = light green, dg = dark green, cr = cream, wh = white, or = orange, mo = medium orange, lo = light orange, gr = green
3 lt = light, md = medium, dk = dark, gr = green, yl = yellow, tn = tan, cr = cream, wh = white
4 Ov = oval, Ob = oblong, Ro = round
5 1 = little or no cracking, 4 = severe cracking and fruit splitting
6 lt = light netting, md = medium netting, hv = heavy, raised netting, na- none.

Cucumber Beetle Control and Its Impact on Bacterial Wilt in Muskmelons

Ric Bessin, Bill Nesmith, Brent Rowell, and John Strang, Departments of Entomology, Plant Pathology, and Horticulture

Introduction

Striped and spotted cucumber beetles can cause serious losses in cucumbers and muskmelons (cantaloupes) in Kentucky. While the adults feed mainly on foliage, stems, pollen, and flowers, their feeding on melon rinds late in the season may reduce market quality. Cucumber beetles are a major concern to muskmelon and cucumber growers because the adults overwinter and vector the bacterium that causes bacterial wilt disease. This disease kills the vines and can severely limit cucumber and cantaloupe production if not managed effectively. While larvae of these insects feed on roots and stems and can cause some damage, this damage is minimal compared to the potential losses due to bacterial wilt.

Commercial melon producers must control cucumber beetles, particularly on young plants. Both species, the striped and the spotted cucumber beetles, are effective vectors of bacterial wilt. Until the early 1990s, growers were able to use Furadan 15G at planting to provide systemic beetle control and reduce the incidence of the disease. However, that insecticide was canceled on cucurbits due to environmental issues. Currently, producers rely on foliar insecticides applied at seven- to 10-day intervals to keep beetle numbers to a minimum. In 2000, a single-year study at UK indicated that a single application of the new systemic insecticide Admire, applied at 20 fluid ounces per acre as a post-transplant drench, provided cucumber beetle control comparable to five weekly foliar applications of Pounce. In 2001, we looked at the protection provided by different rates of Admire 2F applied as a post-transplant drench to Athena melons.

Materials and Methods

A study was conducted at the UK Horticultural Research Farm in Lexington during the summer of 2001 to evaluate the effectiveness of three different rates of Admire 2F for control of cucumber beetles on cantaloupes and the impact of that control on the incidence of bacterial wilt. Four-week-old Athena cantaloupe plants were transplanted into raised black plastic mulched beds with trickle irrigation on May 17 using a waterwheel setter. Plants were spaced 18 inches apart in single rows; beds were 6 feet from center to center. Each experimental plot consisted of four rows of 10 melon plants each. Between each plot, a 60-foot-wide band of corn was transplanted into the rows to reduce cucumber beetle movement between plots.

Admire 2F was applied at three rates (all as post-transplant drenches): 24 fl oz/A per acre (the maximum allowable labeled rate), 16 fl oz/A (minimum labeled rate), and 8 fl oz/A (half the minimum labeled rate), and there was an untreated control. All of the Admire treatments were applied directly to the soil at the base of the plants in 1/3 ounce of water on May 17 immediately after transplanting. The post-transplant drench was selected to minimize worker exposure to insecticide residues while trying to maximize rapid uptake of the insecticide for cucumber beetle control. The Admire was intentionally not mixed with the transplant water because this type of application is prohibited. The application methods used in this study are labeled for commercial use.

Prior to harvest, beetle numbers were monitored by periodically recording the number of striped and spotted cucumber beetles on five plants in each plot and by use of a yellow sticky card in the corner of each plot until plants had "vined" together. Plants within the plots were examined frequently for the occurrence of bacterial wilt (based on wilt symptoms and bacterial streaming) until harvest was complete. Data were subjected to analysis of variance, and means were compared using Fisher's Protected LSD.

Results and Discussion

During the course of this study, the striped cucumber beetle was far more numerous than the spotted beetle and comprised more than 95 percent of the cucumber beetles observed. Generally, numbers of striped cucumber beetles were very high in early June and declined through late July. Yellow sticky card monitoring revealed differences in the number of striped cucumber beetles among treatments (Table 1). During all sampling periods, many more striped cucumber beetles were captured in untreated plots than in any of the Admire-treated plots. There was no significant difference in the number of cucumber beetles captured on yellow sticky cards among the different rates of Admire.

All of the Admire treatments significantly reduced the numbers of cucumber beetles on the plants through June 9 (Table 2). No significant differences were detected in the numbers of these beetles found on the plants among the different rates of Admire. The same results were observed with numbers of live cucumber beetles found on the plants.

This farm has a long history of serious bacterial wilt problems. A high level of bacterial wilt incidence was observed in this study, with more than 70 percent of untreated plants infected by the end of the study. The incidence of bacterial wilt was significantly higher in the untreated plots all season as compared to any Admire treatment. The incidence of bacterial wilt among Admire rates was not different until July 9 when the 8-ounce rate showed more disease (Table 3).

Yields were significantly higher in plots using the labeled rates (16 and 24 fl oz/A) of Admire (Table 4). The plots with the rate below the labeled minimum had significantly lower melon yields. This study indicates that a single application of the systemic insecticide Admire, when used at the full labeled rate of 16 to 24 fl oz/A as a post-transplant drench, provided effective cucumber beetle control for four to six weeks. These data are consistent with our standing recommendations that cucumber beetle control is critical to bacterial wilt control. It must be pointed out that there are alternative application methods listed for cucurbits on the Admire label, but these methods were not evaluated, and the levels of cucumber beetle control, bacterial wilt infection, and melon yields with those methods may not be similar to that obtained with the post-transplant drench method.

Cucumber beetle numbers and the potential threat from bacterial wilt can be highly variable from year to year and between farms in Kentucky. Although only one insecticide treatment was applied in this study, commercial producers should continue to monitor beetle numbers throughout the season and use foliar treatments as necessary if numbers begin to rise. As was reported last year, weekly foliar treatments of recommended insecticides for cucumber beetle control can be highly effective (see Extension publication ID-36, Vegetable Production Guide for Commercial Growers). In some instances, a combination of a systemic insecticide like Admire at planting followed by foliar sprays of a different insecticide may be necessary to maintain effective control. This may be the most economical strategy.

Table 1. Numbers of striped and spotted cucumber beetles per yellow sticky card at Lexington, 2001.
Numbers of Striped and Spotted Cucumber Beetles1
24 fl oz Admire 16 fl oz Admire 8 fl oz Admire Untreated
May 28 1.8 b 2.0 b 1.3 b 46.3 a
June 3 20.8 b 23.3 b 26.3 b 141.3 a
June 9 15.3 b 25.3 b 29.3 b 127.8 a
Jun 18 12.8 b 23.8 b 30.8 b 93.8 a
June 25 8.8 b 9.5 b 10.5 b 25.0 a
1 Means within the same date (row) that are followed by the same letter are not significantly different (LSD>0.05).

Table 2. Numbers of striped and spotted cucumber beetles per 5 plants at Lexington, 2001.

Date

Number of Striped & Spotted Cucumber Beetles1
24 fl oz Admire 16 fl oz Admire 8 fl oz Admire Untreated
May 22 0.0 b 0.0 b 0.0 b 6.5 a
May 28 0.0 b 0.3 b 0.0 b 9.5 a
June 3 0.3 b 0.0 b 0.3 b 29.3 a
June 9 1.3 b 1.8 b 3.8 b 25.0 a
1 Means within the same date (row) that are followed by the same letter are not significantly different (LSD>0.05).

Table 3. Number of plants per plot (40 plants) that had collapsed due to bacterial wilt, Lexington, 2001.
Date 24 fl oz Admire1 16 fl oz Admire 8 fl oz Admire Untreated
June 9 0.0 b 0.0 b 0.0 b 4.5 a
June 18 0.0 b 0.0 b 0.5 b 10.5 a
June 25 0.0 b 0.3 b 1.5 b 18.5 a
July 9 0.3 c 2.8 c 8.3 b 28.3 a
July 17 0.8 c 3.5 c 10.3 b 29.0 a
1 Means within the same date (row) that are followed by the same letters are not significantly different (LSD >0.05).

Table 4. Numbers and weight of marketable fruit per plot (40 plants were initially transplanted into each plot).
Treatment 24 fl oz Admire1 16 fl oz Admire 8 fl oz Admire Untreated
Number of Fruits 84.3 a 76.0 a 51.8 b 11.3 c
Weight of Fruits 447.1 a 398.9 a 256.9 b 56.0 c
1 Means within rows followed by the same letter are not significantly different (LSD >0.05).

Seeded and Seedless Watermelon Variety Trial

John Strang, April Satanek, John Snyder, Darrell Slone, Dave Lowry, Larry Blandford, Spencer Helsabeck, John Holden, Bonnie McCaffrey, and Kirk Ranta, Department of Horticulture

Introduction

Watermelon varieties are introduced by seed companies every year. This trial evaluated seeded and seedless watermelons in order to determine what varieties grow best in Kentucky. Relatively new to the market are seedless, orange-fleshed watermelons that, along with yellow seedless watermelons, are slowly becoming more available and taste much like the traditional red-fleshed varieties.

Materials and Methods

Seeds of 18 seedless and six seeded watermelon varieties were planted in cell packs on April 27. The trays were then placed onto a bench with bottom heat in a warm greenhouse. Once germinated, germination rates were recorded, and the plants were thinned to one plant per cell using scissors. On May 31, the plants were set into raised, black plastic mulched beds with a waterwheel setter. Six plants were spaced 4 feet apart within the row, and rows were spaced 10 feet apart. Each plot was replicated three times, with 8 feet between cultivars. Drip irrigation was used to fertigate and irrigate as needed.

Nitrogen, phosphorus, and potassium were applied preplant to the fields as warranted by soil tests. Two fields out of the three used for watermelons received 150 lbs/A each of phosphate and potash, and 225 lbs/A of ammonium nitrate. The third field received 150 lbs/A of phosphate and 225 lbs/A of ammonium nitrate. A total of 60 lbs/A of ammonium nitrate was fertigated over four applications throughout the season. Irrigation was halted four weeks prior to the estimated harvest time to raise the sugar content of the melons. Admire 2F, a systemic insecticide, was applied to the planting hole immediately after setting the plants at the rate of 24 fl oz per acre. Other foliar insecticides and miticides applied during the growing season included Sevin, Pounce, Asana, and Kelthane. The fungicides Bravo and Quadris were used for disease control. Insect and disease scouting was used to help determine pesticide application timing. Curbit was applied and incorporated into the ground between beds prior to vine cover.

Results and Discussion

During planting and the week following, the weather was unseasonably cold and wet. About half of the plants showed transplant stress and grew slowly the first week. Although vine coverage was heavier than in past years, yield was slightly lower.

Seeded Watermelons

The best performing seeded watermelons in the trial were Stars N' Stripes, Sangria, Athens, and Mara (Table 1). Stars N' Stripes, a large, oblong melon with a distinct mottled rind, had the highest yield. Sangria has been an excellent variety in past years, and there is a tendency for the fruit to be slightly narrow at one end. Athens and Mara also performed very well, and Mara had very large fruit.

Seedless Watermelons

The best performing seedless red watermelons were Millionaire, Triple Prize, Revolution, RWT 8096, and Ultra Cool. Millionaire was the highest yielding and is an excellent round seedless melon with an average sugar content (Table 1). Triple Prize has performed very well in the past and has an exceptional taste (Table 2). It had some hollow heart. Revolution, an elongate, seedless melon, had an excellent taste and yield.

The best performing orange-fleshed seedless watermelon was Orange Sweet. Its flavor and yield were good, but Orange Sweet had more seeds than we would like to see.

Treasure Chest was the best yellow-fleshed seedless watermelon.

Table 1. Seeded and seedless watermelon variety trial yield and fruit characteristics, Lexington, Ky., 2001.
Cultivar Germ.

Rate

(%)

Type1 Shape Seed

Source

Days

to

Harvest

Yield

(cwt/A) 2

Avg.

No. Mkt

Melons

per A

Avg Mkt

Wt

(lb)

No.

Melons/A

<10 lb

Outside

Measurements

Rind

Thick.

(in.)

Sugar

(%)

Length

(in.)

Width

(in.)

Stars N' Stripes 98 S elongate S 85 1290 a 5700 23.1 71 17.7 9.1 0.7 10.8
Sangria 95 S elongate SW 87 1220 ab 5400 22.8 0 16.8 8.7 0.7 12.1
Millionaire 82 T round HM/SW 92 1200 abc 8900 13.4 0 11.7 10.0 1.0 10.4
Athens 99 S elongate SS/SI 82 1110 abcd 4800 17.7 0 14.9 9.4 0.7 11.0
Mara 98 S elongate SI 85 1070 abcd 4400 24.7 0 15.2 9.6 0.7 11.4
Triple Prize 37 T round SW 85 980 abcdef 6300 15.3 653 11.2 10.3 0.8 11.4
Revolution 76 T elongate SS 82 930 bcdefg 4600 16.0 218 13.8 9.0 0.8 11.8
RWT 8096 64 T oval ST/RG 85 910 bcdefg 5900 15.5 0 11.4 9.0 0.7 11.5
Orange Sweet 64 T round SI 84 900 bcdefg 5200 17.1 71 10.5 10.0 0.7 10.2
Ultra Cool 41 T round SI 75 900 bcdefg 6300 14.3 290 9.8 9.7 0.7 12.1
Millenium 91 T round SW/HM 78 700 bcdefg 7000 13.0 582 10.7 8.7 0.6 11.6
Sterling 67 T elongate SW 92 870 cdefg 5000 17.3 0 14.7 8.1 0.8 11.2
Triple Crown 22 T round SW 85 860 cdefg 5700 15.1 0 11.4 9.9 0.8 11.5
Treasure Chest 61 T round RU 80 850 defg 6500 13.0 507 9.2 9.5 0.7 10.8
Crimson Jewel 71 T round RU 83 820 defg 6100 13.6 146 10.1 9.4 0.6 11.3
Crimson Delight 96 S round SW 75 820 defg 3500 24.0 0 11.5 11.1 0.6 10.9
Constitution 74 T round SS 80 800 defg 5400 14.1 290 10.0 9.2 0.7 11.6
Samuri 65 T round SI 85 790 defg 5000 15.6 436 12.1 9.7 0.7 11.6
Freedom 80 T elongate SS/SI 85-90 780 defg 5000 15.9 146 14.1 9.1 0.7 11.1
Buttercup 59 T round JS 85 750 efg 6300 11.7 1160 9.2 9.5 0.6 9.7
Imagination 40 T round SI/RG 85 720 fg 5900 12.3 0 9.8 9.1 0.6 11.1
Orange Sunshine 58 T round SI 85 670 fg 5200 12.8 290 10.2 9.9 0.8 10.9
Black Majic 99 S elongate SI 85 620 g 4400 14.2 71 9.6 9.3 0.5 9.4
4052 Seedless 58 T round SW 85 600 g 3300 18.3 2243 11.1 10.3 0.7 11.0
1 Melon Type S = Seeded, T = Triploid (seedless)
2 Numbers followed by the same letter are not significantly different (Duncan Waller LSD P = 0.05). Marketable yields are based on all melons larger than 10 pounds.

Table 2. Seeded and seedless watermelon variety trial fruit characteristics, Lexington, Ky., 2001.
Variety Uniform.

of Size

(1-5)1

Uniform.

of Shape

(1-5)2

Hollow

Heart

(1-2)3

Flavor

(1-5)4

Avg.

Seed

No./fruit

Interior

Color5

Rind

Type6

Comments
Stars N' Stripes 4 4.3 2.0 4.3 na red CS Attractive interior, juicy, not many seeds, rind has distinctive mottling,"stripes."
Sangria 3.5 3.6 1.8 4.6 na red AS. Attractive interior, some strings in flesh, flavorful.
Millionaire 3.2 3.4 2.0 4.0 3.3 red CS Tiny seeds (3/16 in.) if present, nice flesh texture, flesh a little tough, some sunscald.
Athens 4.3 4.0 2.0 4.1 na dk pink CS Attractive interior, crispy tender textured flesh.
Mara 3 3.7 2.0 4.2 na red RS Attractive, crisp, tender flesh, most fruit are jellybean-shaped.
Triple Prize 2.8 3.5 1.5 4.5 2.0 red dk CS Slightly tough flesh, attractive exterior.
Revolution 2.5 3.5 1.8 4.5 5.0 red RS Attractive interior.
RWT 8096 3.5 3.3 2.0 4.4 0.8 red CS Very tender flesh.
Orange Sweet 2.7 3.4 1.8 3.8 14.3 orange JU Flesh is a bit chewy, firm flesh, attractive interior, orange color varies in intensity throughout. Some BRN7.
Ultra Cool 2.7 3.5 2.0 4.1 1.3 red RS Variability in rind thickness, attractive interior, somewhat chewy.
Millenium 2.8 2.5 2.0 4.2 1.3 pk red BK Very slight ribbing, tough rind.
Sterling 2.5 3.0 1.3 3.9 1.8 dk pink AS Slightly tough flesh, uncharacteristic low yield this season.
Triple Crown 2.7 3.5 1.7 4.2 2.3 lt red RS Firm, chewy flesh.
Treasure Chest 3.3 2.5 2.0 3.9 2.8 br yl JU Attractive interior and exterior, firm flesh, dark seed traces.
Crimson Jewel 2.8 3.4 2.0 4.4 2.3 pk red dk CS Tender, sweet, attractive red flesh.
Crimson Delight 2.3 3.5 2.0 4.1 na dk pink CS Tender flesh, very juicy, delicate texture and taste.
Constitution 2.9 3.3 2.0 4.3 0.5 pk red AS Fibrous material in flesh, tough seed traces, thin rind, tender flesh.
Samuri 2.5 3.0 1.5 4.3 0.8 red RS Tender flesh, juicy, little chewy, nice red color. Some BRN7.
Freedom 3.0 4.0 2.0 4.2 0.8 red dk JU Very attractive exterior and beautiful interior, nice texture.
Buttercup 3.0 3.0 2.0 3.4 1.5 br yl JU Very attractive interior, dark seed traces, firm flesh. Some BRNt.
Imagination 3.0 4.0 2.0 4.1 6.0 dk red BK Attractive interior and exterior, skin has slight white bloom, tender, attractive red flesh, wide difference in taste preferences. Some BRN7.
Orange Sunshine 3.0 3.5 1.8 3.9 9.8 orange RS Very slight hollow heart, seeds gray and numerous.
Black Majic 3.0 4.3 2.0 3.4 na dk pink BK Very thin rind, attractive interior, some fibrous strands in flesh.
4052 Seedless 3.0 4.0 1.8 4.1 4.8 red CS Many off types, some fibrous areas in flesh, crispy flesh. Some BRN7
1 Fruit Size Uniformity 1 = great variation in size, 5 = all the same size.
2 Fruit Shape Uniformity 1 = great variation in shape, 5 = all the same shape.
3 Hollow Heart Rating 1 = hollow heart, 2 = no hollow heart.
4 Informal taste test ratings: 1 = poor, 5 = excellent.
5 Flesh Color lt = light,dk = dark, pk = pink, br = bright, yl = yellow.
6 Rind Type AS = Allsweet, medium green rind w/dark green, broad mottles stripes; JU = Jubilee, light green rind w/distant, narrow, dark green. stripes; BK = Black, solid dark green rind; CS = Crimson Sweet, light green rind w/mottled, dark green stripes; RS = Royal Sweet, light green. rind w/wide, mottled, dark green stripes.
7 BRN = Bacterial rind necrosis.

Watermelon Variety Observation Trial

Anthony Silvernail, Gary Cline, Community Research Service, Kentucky State University; April Satanek, Department of Horticulture

Introduction

This observation trial with seeded and seedless (triploid) watermelon varieties was conducted on the Kentucky State University Research Farm in Franklin County. In this trial, the productivity of two seeded and eight seedless varieties were evaluated according to size and marketable yields.

Materials and Methods

Seeds were planted on April 24, 2001, and on June 7 the seedlings were transplanted by hand into raised, plastic mulched beds. Field preparation consisted of moldboard plowing and two subsequent rototilling operations. Each row (raised bed) was 12 feet apart, and the single plots within each row were 30 feet long and consisted of 10 plants spaced 3 feet apart. Prior to the laying of plastic mulch, nitrogen fertilizer in the form of ammonium nitrate was banded within each row at a rate of 50 lbs N/A. A mid-season application of N was also applied by fertigation at a rate of 20 lbs N/A.

Weed control between beds was accomplished by cultivation and a banded application of Curbit at three weeks after transplanting. Foliar applications of the insecticide Pounce and fungicide Bravo were applied as needed to control insects and diseases.

Results

Rains in late May and early June coupled with mild temperatures delayed planting until the first week of June. Three harvests were conducted from August 16 through September 6. These late summer harvests may have caused the apparent high number of small melons (culls) at the end of the season. However, the summer was generally dry with mild temperatures, and plant vigor was high for all varieties up through the last harvest in early September.

Triploid Watermelons. The highest yielding seedless varieties in terms of marketable melons (> 10 lbs) were Triple Prize, Millionaire, and Millennium (Table 1). Triple Prize was also a top performer in variety trials conducted at the University of Kentucky's Horticulture Research Farm at Lexington in 1999 and 2000. Millionaire appeared to have slightly larger melons, so its overall yield (total weight per acre) was slightly higher than Triple Prize. The worst performing variety was Sterling. In the case of Sterling there appeared to be no pollination and fruit development.

Seeded Watermelons. The highest yielding seeded variety in terms of number of melons per acre (> 10 lbs), average melon weight, and total yield per acre was `Stars and Stripes'.

Table 1. Yields of seeded and seedless watermelon varieties from single plots in Franklin County, Ky., 2001.
Variety Melon

Type1

Germ. % Seed

Source

Days to

Harvest

Mkt. Melon

Wt/A

(>10lb)

No. mkt.

Melons/A

Avg. Mkt.

Melon Wt.

(lb)

No. culls/A

(<10lb)

Outside Measurements Rind

Thickness

(in.)

Length

(in.)

Width

(in.)

Stars and Stripes S 98 AS 85 107230 5082 21.1 605 14.3 8.2 0.6
Anthem S 99 SS/SI 82 74415 3630 20.5 726 13.3 8.2 0.6
Millionaire T 82 HM/SW 92 79279 4356 18.2 302 11.0 90.3 0.5
Millennium T 91 HM/SW 78 50906 4168 12.2 402 9.3 8.0 0.4
Revolution T 76 SS 82 52514 2420 21.7 242 14.0 10.1 0.6
Triple Prize T 37 SW 85 68458 4437 15.4 121 10.1 8.9 0.5
Orange Sweet

T

64

SI

84

63621

2662

23.9

0

13.8

9.6

0.5

Freedom T 80 SS/SI 85-90 59145 3146 18.8 847 13.0 8.0 0.6
Buttercup T 59 JS 85 43451 2541 17.5 484 9.9 9.7 0.4
Sterling T 67 SW 92 0 0 0 0 0 0 0
1 Melon Type S = Seeded, T = Triploid (seedless).

Acorn and Specialty Winter Squash Variety Evaluation

John Strang, April Satanek, John Snyder, Darrell Slone, Dave Lowry, Larry Blandford, Spencer Helsabeck, and John Holden, Department of Horticulture

Introduction

Acorn squash are perennial fall favorites found at any fresh produce stand. They can also be found in markets year around. Acorn squash are situated at the top of winter squash sales. The typical acorn squash is dark, black-green, acorn-shaped, and firm. Recent cultivars have included orange and cream-colored acorn squash. This trial was conducted at the University of Kentucky Horticultural Research Farm in Lexington to determine the best acorn squash varieties for Kentucky growers. Due to wet conditions and high insect populations early in the season, this trial also showcased some of the various cultivars' disease tolerance and plant survival under less than optimal growing conditions.

Methods and Materials

On May 16, 11 acorn squash and seven assorted squash varieties were double-seeded into 72-cell trays in a greenhouse at the Horticulture Research Farm at Lexington. Once germinated, the plants were thinned to one plant per cell. On June 12, squash plants were set into raised, black plastic mulched beds with a waterwheel setter. Six plants were set 4 feet apart within the row, in rows 10 feet apart, with 8 feet between plots. Each plot was replicated four times. Drip irrigation was used to provide water and fertilizer during the season.

Plots received a preplant application of 150 lbs/A of ammonium nitrate; two replications also received an additional 150 lbs/A of potash as warranted by soil tests. During the growing season, a total of 12 lbs N/A was fertigated using ammonium nitrate in three applications. Insecticide and miticide applications included Sevin, Pounce, Asana, and Kelthane. Quadris was applied for disease control. Curbit was applied and incorporated between the beds just prior to vine coverage for weed control. One replication was treated with Basagran prior to planting to control a yellow nutsedge infestation. Plots were scouted weekly, and plants were harvested on August 17 and September 18. Single fruits from each replication at the first harvest were measured and evaluated for quality.

Results

Bacterial wilt was evident four weeks after setting the plants. Cucumber beetles were present at planting, and squash bugs followed shortly thereafter. A number of the plants died prematurely, and the fruit failed to mature. Despite difficult growing conditions, some varieties survived these diseases and insect pests and yielded well.

Acorn squash. Heart of Gold and Carnival were the top producing acorn squash types in the trial (Tables 1 and 3). These cultivars are decorative as well as edible. The exteriors of these squash are cream colored with dark green, mottled stripes. Carnival also has occasional orange patches. Heart of Gold had an excellent flavor. Table Ace and Tay Belle PM were the two best "traditional" dark green acorn squash. Plants of Table Ace held up well and Tay Belle PM, despite high cull numbers and some dead plants, still produced a good yield. Cream of the Crop is a beautiful, cream-colored squash. Table Gold is a very attractive, dark orange acorn squash.

Spaghetti squash. Small Wonder, a small, oval squash, produced very well; the plants held up throughout the season and the fruit consistently looked good (Tables 2 and 4). Hasta-La-Pasta, a larger, bright orange, oblong-fruited plant, succumbed to disease before most fruit matured, creating a lot of decayed fruits, though it did produce some quality fruit.

Kabocha squash. Both cultivars of kabocha squash yielded well, and the vines held up for the entire season. Both Sweet Mama and Delica had dry, extraordinarily sweet flesh. These varieties were considered an excellent substitute for sweet potatoes. The kabocha squash in this trial were harvested later than the other types and sustained some melonworm damage, increasing the number of culls.

Miscellaneous squash. Delicata is an excellent tasting, small, elongated squash. Sugar Loaf is oblong in shape, smaller, and tan, with green mottled stripes. Although both had excellent taste, quality fruit, and convenient serving sizes, they were not heavy producers. Sweet Dumpling had an excellent quality and sweet flesh, but it also had a low yield.

Table 1. Acorn squash yield and fruit characteristics, Lexington, Ky., 2001.
Variety Seed

Source

Days

to

Harvest

Yield

(cwt/A)1

No. Mkt

Fruit/A

Avg.

Fruit

Wt (lb)

Fruit

Length

(in.)

Fruit

Width

(in.)

Flesh

Thick.

(in.)

Culls

(%)

Heart of Gold SW 90 209 b 14100 1.5 4.1 4.9 0.8 3
Carnival HR 85 193 bc 13800 1.4 4.1 4.9 0.8 4
Table Ace HR 85 148 bcdef 9200 1.6 4.8 4.5 0.7 7
Tay Belle PM S 70 140 bcdef 10700 1.3 5.5 4.9 0.9 11
Cream of the Crop SW, HR 85 121 cdefg 7500 1.6 5.1 4.4 0.9 27
Mesa Queen HL, SW 70 120 cdefg 7900 1.2 4.9 4.6 0.8 12
HMX 9736 PM HM 75 95 efg 7900 1.2 4.4 4.3 0.7 4
Table Gold SW 95 93 efg 8000 1.3 4.6 4.0 0.7 14
Table Queen SW 90 80 efg 5900 1.3 5.0 4.4 0.7 16
Tuffy JS 90 78 fg 6800 1.2 4.9 4.3 0.8 34
Table King RU 80 55 g 5400 1.0 4.7 3.6 0.7 64
1 Means followed by the same letter are not significantly different (Waller-Duncan LSD, P = 0.05).

Table 2. Specialty winter squash yield and fruit characteristics, Lexington, Ky., 2001.
Type

Variety

Seed

Source

Days

to

Harvest

Yield

(cwt/A)1

No. Mkt

Fruit/A

Avg.

Fruit

Wt (lb)

Fruit

Length

(in.)

Fruit

Width

(in.)

Flesh

Thick.

(in.)

Culls

(%)

Spaghetti
Small Wonder SW 90 374 a 21300 1.8 5.2 4.9 1.0 7
Hasta-La-Pasta SW 80 184 bcd 8800 2.1 7.7 4.2 0.8 11
Kabocha
Sweet Mama SW 75 189 bc 5100 3.7 4.3 7.1 1.4 10
Delica RU, HR 75 160 bcde 4800 3.4 3.9 7.0 1.2 8
specialty
Delicata HR/JS 100 125 cdefg 13400 0.9 7.2 2.7 0.6 21
Sugar Loaf SW 100 108 defg 12000 0.9 5.1 3.2 0.7 24
Sweet Dumpling HR, SW 100 80 efg 7900 1.0 3.9 4.0 0.7 10
1 Means followed by the same letter are not significantly different (Waller-Duncan LSD, P = 0.05).

Table 3. Acorn squash fruit and vine characteristics, Lexington, Ky., 2001.
Variety Outside

Color1

Inside

Color2

Taste

(1-5)3

Fruit

Uniformity

(1-5)4

Vine

Size5

Comments
Heart of Gold cr w/dg stripes lor 4.2 2.8 Lv Attractive fruit, orange ground spot, vines held up well.
Carnival variable lor 3.5 2.8 Sv Attractive exterior (decorative), majority are cream colored with dark green mottled stripes and orange patches.
Table Ace dg y- or 3.2 3.8 Sv Attractive exterior, heavy fruit, plants held up well.
Tay Belle PM dg mor 4.1 4.0 B Attractive exterior, large fruit, light flesh color, thick, smooth flesh.
Cream of the Crop cr cr 2.7 4.3 B Majority of plants succumbed to disease, many culls from sunburn/rot.
Mesa Queen dg mor 4.2 3.0 Sv Sweet, fibrous, dark orange flesh, vines died in one rep.
HMX 9736 PM dg mor 3.7 3.1 B Numerous culls due to sunburn/rot, vines didn't hold up.
Table Gold dk or dor 3.3 3.2 B Very bright orange exterior, some with yellow stems.
Table Queen dg mor 3.9 3.1 Sv Rind not colored well, sweet, fine texture, many vines died.
Tuffy dg y-or 4.4 3.0 Sv Deeply grooved, slightly long and narrow for an acorn squash, dry, fine grained flesh, nice squash flavor.
Table King dg y-or 3.8 2.5 B Unattractive, color variable, sunburned, small, poor quality fruit.
1 Outside color cr = cream, dg = dark green, or = orange, variable = see comments
2 Inside color l = light, m = medium, d = dark, or = orange, y = yellow, cr = cream, abl = yellow
3 Informal taste test scores: 1 = bland, unpleasant taste, 5 = sweet, pleasant consistency
4 Fruit uniformity 1 = extremely variable, 5 = very uniform
5 Vine size Lv = large vine, Sv = small vine, B = bush

Table 4. Miscellaneous squash fruit and vine characteristics, Lexington, Ky., 2001.
Type

Variety

Outside

Color1

Inside

Color2

Taste

(1-5)3

Fruit

Uniformity

(1-5)4

Vine

Size5

Comments
Spaghetti
Small Wonder md or y-or 3.3 4.3 Sv Nice looking fruit, vines and fruit held up well.
Hasta-La-Pasta dk or mor 3.6 3.3 Sv Very good orange color outside and inside, many fruit did rot.
Kabocha
Sweet Mama dg w/ lg stripes dor 4.5 3.6 Lv Nice fruit, very large seeds.
Delica dg w/ lg stripes dor 4.6 3.9 Lv Attractive, very sweet flavor with a nice texture, vines held up well.
specialty
Delicata cr w/dg stripes lor 4.1 3.1 Sv Attractive fruit, vines held up well.
Sugar Loaf tn w/ dg stripes lyl 4.2 1.6 Sv Attractive fruit, sweet dry flesh, vines held up very well.
Sweet Dumpling cr w/dg stripes dyl 4.5 2.8 Sv Attractive exterior, excellent taste, all plants died in one rep.
1 Outside color dg = dark green, lg = light green, md = medium, cr = cream, dk = dark, or = orange, tn = tan.
2 Inside color l = light, m = medium, d = dark, or = orange, y = yellow, cr = cream.
3 Informal taste test scores: 1 = bland, unpleasant taste, 5 = sweet, pleasant consistency.
4 Fruit uniformity 1 = extremely variable, 5 = very uniform.
5 Vine size Lv = large vine, Sv = small vine, B = bush.

Sweet Corn Cultivar Evaluation for Northwestern Kentucky

Thomas J. Brass and Charles Mulligan, Kentucky Cooperative Extension Service, Henderson County, Henderson, Kentucky

Introduction

The objective of this study was to compare 22 sugary-enhanced (se) sweet corn cultivars and the standard (su) cultivar Silver Queen for direct market use by evaluating plant, ear, yield, and flavor characteristics.

Materials and Methods

The selected plot area was established on a Loring silty clay soil. In late April, the plot was disked, and 250 lb/A of 15-15-15 and 220 lb/A of 34-0-0 (NH4NO3) were applied. The pH was 6.2, and no lime was added. The plot was separated into three sections so that sweet corn of different colors could be segregated, reducing or preventing cross-pollination. The plot was planted on May 10, consisting of rows 20 feet long and 3 feet apart with 50 seeds planted per row for a desired final stand of 30 plants per row. Germination, while delayed by weather conditions, was good for all varieties, and plants were manually thinned to 30 plants per row. The experimental design was a randomized complete block with four replications. Following planting, atrazine + metolachlor (Bicep 6L) at 1.2 + 1.5 lb ai/A, respectively, was surface applied. Ammonium nitrate was sidedressed at 100 lb /A when plants reached 8 inches in height. Permethrin (Pounce 3.2EC) was used at 0.2 lb ai/A for insect control starting at the tassel stage followed by another application during ear development. Observations included plant height, ear height above ground, ear length and diameter, shuck cover, tip fill, yield, and average ear weight. An informal taste test was performed, sampling at least 20 ears of each variety.

Results and Discussion

White Corn Varieties. The performance of white sweet corn varieties is summarized in Table 1. The white variety 94H263 again proved to be an excellent early-maturing selection for ear length, marketable yield, and flavor. Likewise, Avalanche and Silver King were the top producers and best tasting late-maturing varieties.

Yellow Corn Varieties. The performance of yellow sweet corn varieties is presented in Table 2. Welcome, a new early-maturing yellow sweet corn variety, had good flavor but did very poorly in all other characteristics evaluated. The newer variety Gold Nuggets also had good flavor but did not yield as well as last year. Weather conditions at time of planting were very warm and dry. This was followed by unusually cool weather that caused a 1½-week delay in harvest of many early-maturing varieties tested. These weather conditions may have played a part in the extremely low yields of Welcome and Gold Nuggets. The varieties Honey Select and Bodacious proved again that they are all-around high yield and high quality yellow sweet corn varieties.

Bicolor Corn. The performance of bicolor sweet corn varieties is summarized in Table 3. All bicolor varieties tested were very similar in ear length, shuck cover, and marketable yield. However, like the early-maturing yellow varieties, the early-maturing varieties Peaches and Cream and Temptation also had low yields, probably a reflection of the poor weather conditions early in the growing season. The variety Parfait, the current and past best flavored bicolor sweet corn variety, also was the top yielding variety in this year's trial. Over the past few years, this variety was an average performer for marketable yield. Other varieties that had good flavor and yield included Mystique, a newer variety that also performed well last year and a new variety, Buckeye.

Table 1. White sugary-enhanced (se) and Silver Queen sweet corn plant, ear, yield and flavor characteristics in Henderson County, Kentucky, 2001.
Cultivar

(Seed Source)

Maturity1

(Days)

Plant Height2 (in.) Ear Height3 (in.) Ear Length (in.) Ear Diameter (in.) Shuck Cover4 (in.) Tip Fill5 (in.) Marketable Ears (no./plot) Ave Wt.

5 Ears Husked (lb)

Flavor6 (1-4)
94H263 (SW) 70 66 D-F7 17 D 7.1 C 6.2 A 2.5 C-D 0.0 A 24 A-C 2.1 C 3.4 A
Silver Princess(RG) 74 65 E-F 19 B-D 8.0 A-B 6.0 A-B 1.3 E 0.0 A 18 B-C 2.6 A 2.9 C-D
Faith (SW) 77 65 B 21 B-C 8.1 A-B 5.8 A-B 0.8 E 0.0 A 18 C 2.1 C 2.6 D
Imaculata (RU) 78 71 D-E 21 B-C 7.4 B-C 5.9 A-B 3.6 A 0.0 A 23 A-C 2.1 C 3.0 B-C
Fantasia (S) 78 79 B-C 22 B 7.1 C 5.6 B 3.3 A-B 0.2 A-B 24 A-B 2.1 C 2.7 C-D
Avalanche (RU) 78 74 C-D 20 B-C 7.8 A-C 5.7 B 1.3 E 0.0 A 28 A 2.3 B-C 3.5 A
Frosty (RU) 80 61 F 15 D 7.7 A-C 6.0 A-B 2.2 D 0.0 A 26 A 2.2 B-C 3.1 B-C
Silver King (SW) 82 86 B 22 B 8.3 A 5.8 A-B 2.9 B-C 0.0 A 26 A 2.5 A-B 3.6 A
Silver Queen (WI) 92 95 A 28 A 8.1 A-B 5.6 B 1.2 E 0.1 A-B 19 B-C 2.7 A 3.0 B-C
LSD P = 0.05 8 4 0.9 0.4 0.6 0.2 7 0.3 0.3
1 Relative days to maturity.
2 Distance from ground to top leaf at R6 stage of growth for 5 random samples of each replicate.
3 Distance from ground to bottom of ear for 5 random samples of each replicate.
4 Distance shuck extends beyond ear tip for 3 random samples of each replicate.
5 Distance of unfilled kernels at ear tip for 3 random samples of each replicate.
6 Flavor: 1 = Poor; 2 = Good; 3 = Very Good; 4 = Excellent.
7 Means followed by same letter do not significantly differ (P = 0.05, LSD).

Table 2. Yellow sugary-enhanced (se) sweet corn plant, ear, yield and flavor characteristics in Henderson County, Kentucky, 2001.
Cultivar

(Seed Source)

Maturity1

(Days)

Plant Height2

(in.)

Ear Height3

(in.)

Ear Length

(in.)

Ear Diameter

(in.)

Shuck Cover4

(in.)

Tip Fill5

(in.)

Marketable Ears

(no/plot)

Ave Wt.

5 Ears Husked

(lb)

Flavor6

(1-4)

Welcome (RU) 70 46 C-D7 11 B 6.7 B 5.6 B-D 1.9 B 0.0 A 9 E 1.6 E 3.7 A-B
Gold Nuggets (RU) 75 65 A-B 22 A 6.9 A-B 5.9 B-C 2.6 A 1.1 C-D 13 D-E 2.2 C 3.8 A
Bodacious (SW) 75 56 B-C 20 A 7.5 A-B 5.5 C-D 2.2 A-B 0.4 A-B 28 A-B 2.0 C-D 3.6 A-B
Kandy Plus (RG) 75 75 A 24 A 8.0 A 6.6 A 1.6 B 0.9 B-D 17 C-D 3.4 A 3.5 A-B
Amaize (RU) 75 43 D 12 B 7.2 A-B 5.4 D 1.9 B 0.0 A 20 C-D 1.9 D 2.4 D
Honey Select (RG) 79 73 A 23 A 7.8.A-B 6.0 B 2.1 A-B 0.5 B-C 35 A 2.8 B 3.4 B
Incredible (SW) 85 74 A 22 A 7.2 A-B 6.0 B 2.1 A-B 1.2 D 25 B-C 2.7 B 3.0 C
LSD P = 0.05 12 7 1.2 0.5 0.8 0.6 7 0.4 0.4
1 Relative days to maturity.
2 Distance from ground to top leaf at R6 stage of growth for 5 random samples of each replicate.
3 Distance from ground to bottom of ear for 5 random samples of each replicate.
4 Distance shuck extends beyond ear tip for 3 random samples of each replicate.
5 Distance of unfilled kernels at ear tip for 3 random samples of each replicate.
6 Flavor: 1 = Poor; 2 = Good; 3 = Very Good; 4 = Excellent.
7 Means followed by same letter do not significantly differ (P = 0.05, LSD).

Table 3. Bicolor sugary-enhanced (se) sweet corn plant, ear, yield and flavor characteristics in Henderson County, Kentucky, 2001.
Cultivar

(Seed Source)

Maturity1

(Days)

Plant Height2

(in.)

Ear Height3

(in.)

Ear Length

(in.)

Ear Diameter

(in.)

Shuck Cover4

(in.)

Tip Fill5

(in.)

Marketable Ears

(no./plot)

Ave Wt.

5 Ears Husked

(lb)

Flavor6

(1-4)

Peaches and

Cream (SW)

70 73 A-B7 19 B-C 7.6 A-B 6.0 A-C 2.2 A 0.7 C-D 15 B 2.4 B-C 2.8 B-C
Temptation (RU) 71 64 B 18 C 7.4 A-B 6.3 A 2.0 A 0.1 A-B 16 B 2.4 B-C 2.6 C
Bon Appetit (RU) 74 65 B 20 B-C 7.7 A-B 6.1 A-B 1.8 A 0.0 A 20 B 2.8 A 2.0 D
Buckeye (RU) 74 69 A-B 24 A-B 7.8 A-B 5.5 B 2.9 A 0.0 A 19 B 2.3 C 3.6 A
Mystique (RU) 75 70 A-B 22 A-C 7.8 A-B 5.9 B-C 2.0 A 0.2 A-B 20 B 2.8 A-B 3.7 A
Parfait (SW) 76 81 A 26 A 8.1 A 5.8 C-D 0.1 B 1.1 D 27 A 2.1 C 3.8 A
Serendipity (RG) 82 74 A-B 22 A-C 7.0 B 6.0 B-C 2.9 A 1.2 D 19 B 2.4 B-C 3.1 B
LSD P = 0.05 12 5 0.9 0.4 1.1 0.7 7 0.4 0.4
1 Relative days to maturity.
2 Distance from ground to top leaf at R6 stage of growth for 5 random samples of each replicate.
3 Distance from ground to bottom of ear for 5 random samples of each replicate.
4 Distance shuck extends beyond ear tip for 3 random samples of each replicate.
5 Distance of unfilled kernels at ear tip for 3 random samples of each replicate.
6 Flavor: 1 = Poor; 2 = Good; 3 = Very Good; 4 = Excellent.
7 Means followed by same letter do not significantly differ (P = 0.05, LSD).

Broiler Litter Effective as Sweet Corn Fertilizer and Soil Conditioner

Thomas J. Brass, Henderson County Cooperative Extension Service, Henderson, Kentucky

Introduction

Over the past decade, Kentucky has seen major increases in broiler production, marketing 188.8 million birds in 1999. During the course of a year, these broilers can produce close to a half million tons of litter. Proper disposal of broiler litter is a concern since its repeated application to agricultural land can cause phosphorus accumulation in surface soil that is susceptible to losses through runoff and erosion.

One option is disposal of broiler litter on land used for horticultural production. Benefits of using broiler litter for production of value-added crops such as vegetables have not been extensively investigated. Applying broiler litter to vegetable crops like sweet corn would give broiler producers another disposal option.

The objectives of this study were to determine if poultry litter can be used as the only source of nitrogen (N) for sweet corn production and to determine the effect of broiler litter on soil bulk density.

Materials and Methods

This two-year study was conducted on two separate plots of Loring silt loam soil. Plots were planted with Silver King sweet corn on 1 June 2000 and 10 March 2001, respectively. In each year, the experiment included 12 treatments. One treatment received no nitrogen and another treatment received 50 lb of N applied as a sidedress of ammonium nitrate when plants were 12 inches tall. Five treatments were preplant incorporated using a total of 150 lb of N from poultry litter (PL) and/or ammonium nitrate (AN) as follows: 0 percent PL/100 percent AN; 25 percent PL/75 percent AN; 50 percent PL/50 percent AN; 75 percent PL/25 percent AN; and 100 percent PL/0 percent AN. The other five treatments received preplant incorporation of only 100 lb of N from PL and/or AN in the same five combinations as previously mentioned. These treatments also received a sidedress application of AN (50 lb of N) when plants were 12 inches tall.

All plots consisted of three rows, each 40 feet long and 3 feet apart with 100 seeds planted per row for a desired final stand of approximately 23,000 plants per acre. The middle row of each plot represented an experimental unit. All 12 treatments were replicated four times and arranged in a randomized complete block design.

Prior to planting, applications of PL and AN were incorporated 6 inches deep with a standard disk. Atrazine plus metolachor (Dual II) at 1.2 + 1.5 lb ai/A, respectively, was applied two days after planting.

Plant height was measured at the reproductive silking (R1) stage of growth on five random plants in each plot. Marketable number of ears and marketable yield were measured following harvest. Soil bulk density after harvest was measured using a standard core method (3 inches deep). All data were subjected to analyses of variance to test for main effects, and regression analyses were used to determine rate responses to application ratios of PL and AN and to sidedress treatments.

Results and Discussion

Total N from PL produced a similar or superior sweet corn response for all measurements taken when compared to the AN treatment; however, while not always statistically significant, applying 75 percent PL /25 percent AN nitrogen ratios tended to produce the greatest response.

With regard to treatments that received 150 lb of N, sidedressing just more than 30 percent of plant N requirements with AN after plants reached 12 inches tall had no effect on any of the final measurements recorded. This was true when either PL or AN was used as the preplant N treatment (data not shown).

Plant height (Figure 1) of sweet corn increased linearly with higher ratios of poultry litter incorporated. Plant height was less for the control when compared to all other treatments.

Treatment effects for marketable ears (Figure 2) and yield (Figure 3) increased linearly with higher ratios of poultry litter applied, but a curvilinear relationship was also established for both sweet corn yield and weight—presumably related to the 75 percent PL treatment effect.

Regardless of fertilizer treatment, marketable yield of sweet corn was greater than that of the unfertilized control. Sweet corn grown in plots with 100 percent AN had a 31 percent higher yield than the control plots but was at least 11 percent lower in yield when compared to plots with 50 percent PL or more. Sweet corn grown in 75 percent PL plots had a higher marketable yield than sweet corn in 100 percent AN plots and similar yields when compared to the other PL plots.

Soil bulk density following harvest decreased linearly by adding larger ratios of poultry litter to the soil (Figure 4). Applications of litter at the 50 percent ratio and above resulted in bulk densities significantly lower than the control. While not significant, the addition of 100 percent AN showed a substantial decrease in soil bulk density when compared to the control. This may be explained by the potentially larger root system produced by sweet corn in response to AN applications. Increased root mass tends to break up soil density and, in turn, produce bulky, unstable pedons within the effective root zone.

Conclusions

Plant growth and yield results indicated that broiler litter can be used as an alternative, and possibly superior, source of fertilizer N on sweet corn. With regard to sweet corn receiving the recommended rate of N, all fertilizer can be applied at or just prior to planting since sidedressing did not prove to be any more beneficial to plant growth or yield. Based on results of this study, the ideal ratio of poultry litter and ammonium nitrate N fertilizer appears to be 75 percent PL and 25 percent AN. This may be explained by the presumption of quick N availability from ammonium nitrate to initiate plant growth followed by slower N release from poultry litter through the rest of the growing season.

A ton of broiler litter generally contains about 60 pounds of N, of which about 60 percent (36 pounds) will be available the year it is applied. Therefore, a sweet corn crop requiring 150 pounds of fertilizer N per acre, using a 75 percent PL/25 percent AN ratio, would need 3.1 tons of PL (113 pounds total N) and 110 pounds of AN (37 pounds total N), respectively, per acre. Another benefit of using this ratio is reducing potential long-term phosphorus build-up in the soil that may occur when PL is the sole source of N.

Acknowledgments

The author would like to thank Charles Mulligan and Michael Reeder, both of Henderson County, for hosting the trials and Sandefur Farms, McLean County, for supplying chicken litter. The author also expresses appreciation to Greg Hefton of Hanson Spreader Service, Hopkins County, for supplying chicken litter and his custom spreading services. The experiment was funded in part by a SARE grant through Greg Henson, County Extension Agent for Agriculture, McLean County.

Figure 1. Effect of ammonium nitrate and poultry litter treatments on final sweet corn height.

Figure 2. Effect of ammonium nitrate and poultry litter treatments on sweet corn marketable yield.

Figure 3. Effect of ammonium nitrate and poultry litter treatments on sweet corn marketable weight.

Figure 4. Effect of ammonium nitrate and poultry litter treatments on soil bulk density following harvest.

All America Selections Vegetable Display Gardens

Richard Durham and Shari Dutton, Department of Horticulture

Introduction

Recent All America Selections (AAS) winners are promoted through a nationwide display garden program. Many display gardens are associated with AAS trial gardens; however, the host institution need not be involved in the AAS trial program to sponsor a garden. The display garden can be planted with AAS vegetable selections, flower selections, or both. In 2001, an AAS vegetable display garden was planted at the University of Kentucy to demonstrate performance of recent selections to home gardeners and commercial producers.

Materials and Methods

The main display garden was located at the University of Kentucky Lexington-Fayette County Arboretum (UK Arboretum). Secondary plantings were made for display during field days and other events at the University of Kentucky Horticultural Research Farm in Lexington and at the University of Kentucky Research and Education Center at Quicksand. Selections planted are listed in Table 1. All plants were initially seeded in plug trays in the greenhouse and later transplanted to the field. Most transplanting was accomplished by late May. Evaluations were based primarily on the planting at the UK Arboretum unless otherwise noted. At the UK Arboretum, plants were sidedressed with ammonium nitrate at transplanting and again four to eight weeks after transplanting, depending on planting date. No insecticides were applied at the arboretum with the exception of two applications of organically approved Bt for control of worms on cabbage.

Results and Discussion

Cabbage F1 `Dynamo'

This cabbage produced a small, dense head weighing 2 to 2.5 pounds. There was no evidence of head splitting, and harvests were made over an extended period from early June to late July with little decrease in quality. The compact size of plants made this cabbage very suitable for home gardens, and the prolonged harvest window made possible by the resistance to head splitting may make it attractive to commercial growers.

Cabbage F1 `Savoy Express'

Savoy Express is promoted as being a relatively early savoy type cabbage that is compact and produces a small head (1 to 1.5 pounds). The plants grew very well after transplanting, but some wet weather around the time the heads were maturing caused a lot of internal and basal rot of the heads. This was much less of a problem with Dynamo, which was growing nearby.

Okra F1 `Cajun Delight'

Cajun Delight was slow to establish from transplanting and may have established better by direct seeding. Nevertheless, once established, the plants produced consistent yields of one to two pods per plant per week. A highlight of this variety was its earliness, with the first edible-sized pods produced 60 days after transplanting.

Thai Basil `Siam Queen'

This basil produced a densely branched plant without the need for pinching, resulting in high yields of licorice-scented leaves. The plants reached a height of 28 to 30 inches, had equal spread, and exhibited little lodging. A drawback to this variety was that there was little regrowth of plants after being cut back.

Lemon Basil `Sweet Dani'

Sweet Dani is an attractive plant that can be grown for both culinary and ornamental purposes. The plants were more compact than Siam Queen and reached a height of around 20 inches. The inflorescence also remained compact, with deep maroon to dark purple flowers. Sweet Dani also responded better to cutting back than Siam Queen by producing additional growth. Even without cutting back, Sweet Dani produced a second flush of growth; however, this made the plants less attractive due to the remaining presence and decline of the initial inflorescence.

Swiss Chard `Bright Lights'

This plant received a lot of attention due to its bright rainbow of stem colors and robust size, which was up to 30 inches tall with equal spread. It has been used for both culinary and ornamental purposes. The foliage stays mild-flavored throughout the growing season, and new foliage was continually produced as the older leaves were removed. Interestingly, at the UK Arboretum plants were fed upon regularly by goldfinches. The feeding occurred at the tips of the leaves and was not excessively damaging. Most who saw them agreed that the attraction of the goldfinches to the Swiss chard was a benefit and not a liability, and this might add to the attractiveness of Bright Lights in the home garden.

Pumpkin `Wee-B-Little'

Wee-B-Little was a miniature, ornamental type pumpkin with mature fruit weighing only about 1 pound. The plants were fairly compact and spread only 6 to 8 feet. This pumpkin was slow to establish at the UK Arboretum, with only 25 percent of plants surviving four weeks after transplanting. The remaining plants declined due to squash vine borer before the pumpkin fruit matured. Better growth was achieved at the Horticulture Research Farm, where plants were grown on black plastic mulch with drip irrigation and received insecticide treatments. There the fruit did mature. The fruit were attractive, and an added benefit was that the peduncle, or fruit stalk, is essentially spineless, making it easier to handle. For home production, one would be advised to apply early preventive insecticide sprays for squash vine borer.

Squash `F1 Eight Ball'

Eight Ball is a zucchini-type squash but one that is perfectly round. The plants bore fruit very early, 25 to 30 days after transplanting (about 35 to 40 days after seeding), and yields were high. Although Eight Ball is described as having a compact growth habit, it still reached 2.5 to 3 feet tall and spread 3 to 4 feet. The plants fell victim to squash vine borer by early August but had already produced a good crop of squash. The fruit were most tender if picked when 2 to 3 inches in diameter but were still very usable when more mature—even up to 5 inches in diameter.

Tomato F1 `Juliet'

This variety produced small, cherry-type tomatoes with elongated, red fruit that reached about 1 ounce in size. The plants were grown in cages, and the yields were very high. The fruit was very resistant to cracking, but quality was marginal since the fruit did not achieve good sugar content until late in the season—possibly due to cloudy, rainy weather and high plant vigor early in the season that changed to increased moisture stress and decreased plant vigor later in the season. The indeterminate growth habit made these plants difficult to contain in the cages, and it was necessary to prune vines occasionally to contain growth.

Tomato F1 `Jolly'

Jolly is a larger (1.5 ounce) cherry-type tomato that produces pink, peach-shaped fruit with a distinguishable point on the blossom end. Fruit tended to crack later in the season, and overall quality was not exceptional. The plants were prolific, with high yields and vigorous growth that required frequent pruning.

Watermelon F1 `New Queen'

New Queen was difficult to establish at the UK Arboretum. Plants generally lacked vigor, and only 50 percent of the plants survived longer than four weeks. The remaining plants set very few fruit, and the fruit did not mature. Plants at the Horticulture Research Farm did much better, likely due to the increased soil temperatures and more even soil moisture provided by the black plastic mulch and drip irrigation. New Queen produced an orange-fleshed, icebox-sized, seeded melon.

Sweet Corn F1 `Indian Summer'

Indian Summer is marketed as the first sweet corn with multicolored kernels. It also contains the sh2 genotype resulting in supersweet kernels. Ears ripened about 79 days after planting. The small plot at the UK Arboretum (4 feet by 6 feet) produced some nicely filled ears. However, if this variety is being grown solely for brightly colored kernels, the gardener may be somewhat disappointed. The kernels do color, mostly in various shades of purple or yellow, but do not achieve their best color until the ears are very mature or even over-mature. The color darkens with cooking but also washes out to some extent, causing the water in the pot to turn dark. With these drawbacks in mind, Indian Summer with its colored kernels is still a fairly nice novelty corn suitable for the home gardener. Be aware that because of the sh2 genetics, the kernels will shrivel as they dry, and the ears will not be suitable for use in fall decorations.

Sweet Corn F1 `Honey Select'

This is a yellow sweet corn that combines supersweet (sh2) and sugar enhanced (se) genetics into one variety. Ears were at the edible stage at around 80 days. In the small (4 feet by 6 feet) plot at the UK Arboretum, pollination and ear fill were surprisingly good. Kernels were very tender, and overall quality was good, certainly better than Indian Summer.

Pea `Mr. Big'

Mr. Big is an English-type pea grown mostly for shelling, although some immature pods were also very edible. Plants were direct seeded in early April, and even with a late start date, the plants produced a good crop. Mature pods were larger than in most varieties, making it easy to spot the pods on the plant and easy to shell the peas. Plants continued to produce until late June.

Pepper F1 `Blushing Beauty'

This sweet pepper produces colored fruit on compact plants, making it a good addition to home gardens or even suitable in edible landscape-type situations. The fruit began pale yellow to ivory, became more yellow as it matured, then ripened to a bright orange red. The fruit flavor was good but not exceptional. There are certainly many green bell varieties with superior fruit quality, but the color progression of the fruit makes Blushing Beauty noteworthy. Good yields were achieved all summer until frost.

Pepper F1 `Giant Marconi'

Giant Marconi is marketed as an Italian grilling pepper, but it can also be used fresh as one would use bell peppers. The fruit are large, up to 8 inches long and 2 to 3 inches in diameter. They are dark green when immature, maturing to a deep red. The core and seeds are restricted to the stem end, making them easy to remove while maintaining the shape of the pepper. Mature fruit were extremely sweet when roasted. Yields were very high on bushy, 30-inch tall plants. Production continued until frost. This is another entry that may have potential for roadside or farmers' markets.

Onion F1 `Super Star'

Super Star was undoubtedly the most talked about entry in the AAS vegetable display garden. Exceptionally large bulbs (generally 1 pound or more) were produced about half submerged in the soil, making these onions real eye-catchers. Even though bulbs were exposed to sun, no sun scorch was noticed. When harvested immature, the bulbs had a very mild, sweet flavor and were suitable for eating fresh. As the bulbs matured, they became more pungent but were still suitable for some fresh uses but especially for use in cooking. Mature bulbs were successfully stored for four to six weeks. Bulbs for storage were harvested 100 days after transplanting. Further evaluation is necessary, but Super Star may well have potential for commercial production, especially for roadside or farmers' markets.

Acknowledgments

Thanks to Terry Jones for transplanting and caring for the vegetable display garden at Quicksand and to April Satanek for helping with transplanting the vegetable display garden at the Horticulture Research Farm.

References

All America Selections, 1311 Butterfield Road, Suite 310, Downers Grove, IL 60515.
Web site: www.all-americaselections.org.

Table 1. All America vegetable selections included in the display garden.
Selection AAS selection year
Cabbage F1 'Dynamo' 1997
Okra F1 'Cajun Delight' 1997
Thai Basil 'Siam Queen' 1997
Lemon Basil ' Sweet Dani' 1998
Swiss Chard 'Bright Lights' 1998
Pumpkin 'Wee-B-Little' 1999
Squash F1 'Eight Ball' 1999
Tomato F1 'Juliet' 1999
Watermelon F1 'New Queen' 1999
Sweet Corn F1 'Indian Summer' 2000
Cabbage F1 'Savoy Express' 2000
Pea 'Mr. Big' 2000
Pepper F1 'Blushing Beauty' 2000
Onion F1 'Super Star' 2001
Pepper F1 'Giant Marconi' 2001
Tomato F1 'Jolly' 2001
Sweet Corn F1 'Honey Select' 2001

Yield and Disease Ratings for Heirloom Tomato Varieties

Richard Durham, John Hartman, and Roger Postley, Departments of Horticulture and Plant Pathology

Introduction

Heirloom or heritage vegetables are gaining in popularity, with home gardeners and commercial producers marketing through roadside stands and farmers' markets. Reasons for this increase in popularity include ethnic or regional preferences for certain cultivars and the belief that heirloom cultivars have superior fruit quality as opposed to those bred for specific marketing characteristics such as shelf life, firmness, and uniform ripening. This study was undertaken to evaluate a limited number of heirloom tomato cultivars for yield and disease incidence under Kentucky growing conditions. The recommendations from this study are mainly for home gardeners, although commercial producers might also find useful information.

Materials and Methods

A group of seven heirloom tomato varieties, all indeterminate types, were selected for evaluation along with three indeterminate control varieties (Beef Master, Better Boy, and Early Girl) commonly grown in home gardens (Table 1). Most varieties were seeded in the Horticulture Greenhouse (UK campus) on 2 April except for Mr. Stripey and Buck's Co. Hybrid, which were seeded on 9 April. Seeds were sown directly into 126-cell plastic trays. Transplanting to the field occurred on 30 May at the UK Horticultural Research Farm in Lexington. A plot consisted of five plants of a single variety, spaced 18 inches apart in a single row, on 6-inch-high raised beds spaced 6 feet apart, with black plastic mulch and trickle irrigation. Plots were not replicated. Drip irrigation was applied as needed. Plants were staked (to 5 feet), tied using the Florida weave system, and pruned to two main stems. Fifty pounds of nitrogen was applied as ammonium nitrate prior to bed formation, and a total of 10 additional pounds of nitrogen (divided into three applications) was applied with irrigation water. Plots were not treated with fungicides so that disease susceptibility could be evaluated. Insecticides were applied only as needed.

A total of five harvests were made from 20 July to 4 Sept. Yield was calculated as the total fruit picked from five-plant plots over the five harvest dates. On two harvest dates, 14 August and 24 August, fruit were graded into the following size classes: jumbo (> 3.5 inches in diameter), extra large (> 2.75 inches but < 3.5 inches), large (> 2.5 inches but < 2.75 inches), medium, and small (< 2.5 inches). Fruit were also sorted according to U.S. No. 1 or U.S. No. 2 grades. A quality score for each variety was calculated by combining the weight of all fruit considered marketable (size class large and above, U.S. No. 1 grade) divided by the total amount of fruit picked for that variety on the two dates when size classes were evaluated. Disease observations were made for early blight, powdery mildew, and tomato mosaic virus with the final disease evaluation made on 21 August.

Results and Discussion

In general, the heirloom varieties grew very well under the production conditions described. However, these indeterminate types would have benefited from taller and sturdier stakes and increased in-row spacing. The disease incidence noted in Table 1, especially with regard to powdery mildew, may have been less severe with increased in-row spacing. It was noticed that fungal diseases were more severe on the west side of each plot than on the east side, presumably due to earlier drying by the morning sun on the east side. Wider spacing may have also allowed for faster drying of foliage by allowing better air circulation within and between plants.

When compared to controls, three heirloom varieties, Buck's Co. Hybrid, Pink Odoriko, and German Johnson, performed particularly well in this trial (Table 1). Buck's Co. Hybrid had the highest fruit quality of any variety in the study and yields that were comparable to two of the three control varieties. This variety produced deep red, round fruit that were very firm and smooth when ripe. Pink Odoriko produced higher yields than the control varieties, but this was offset by lower fruit quality, primarily due to cracking and small fruit. This variety produced round pink fruit that were also very firm and smooth at maturity. German Johnson had highest yields of any of the heirloom varieties, but this was offset by a fruit quality rating of only 50. The fruit quality was most affected by cracking and roughness of the fruit, which caused many fruit to be classified as U.S. #2, or culls. One other variety, Delicious, appeared promising. Yields for this variety were lower than the three previously mentioned, but the fruit were dark red, smooth, and generally fell in the large to extra-large size category. Some cracking resulted in lower fruit quality.

Two of the poorer performing varieties, Big Rainbow and Mr. Stripey, were low in yield and fruit quality because many of the fruit developed bacterial soft rot prior to picking. Fruit with this condition were removed from plants but not included in yield totals. Under home garden or commercial production where preventative fungicidal sprays are applied to control early blight, the soft rot may be less severe. Giant Belgium exhibited low yield more because of lower fruit set than from any fruit disease problem. The lower fruit quality score was due to excessive cracking and roughness of the fruit.

This initial trial of heirloom tomatoes was meant to evaluate a few varieties for their suitability for home garden production and gather preliminary data regarding whether any might be promising for commercial production. From this initial study, Buck's Co. Hybrid, Pink Odoriko, German Johnson, and possibly Delicious can be recommended to home gardeners. Buck's Co. Hybrid, with its high fruit quality and relatively high yields, may also be suitable for commercial production.

Acknowledgments

Thanks to April Satanek and Shari Dutton for assistance with transplanting and to Brent Rowell for assistance in fruit quality grading.

Table 1. Yield, fruit quality, and disease rating of heirloom tomato varieties.
Variety (seed source) Yield (lb)1 Fruit Quality (%)2 Disease rating3
Heirlooms EB PM V
Big Rainbow (BU) 19.8 42 25 35 (-)
Buck's Co. Hybrid (BU) 35.7 65 15 20 (++)
Delicious (BU) 31.0 51 30 0 (+)
German Johnson (TGS) 49.8 50 25 20 (-)
Giant Belgium (TT) 21.0 46 55 60 (+)
Mr. Stripey (J) 21.9 40 20 20 (+)
Pink Odoriko (TGS) 44.4 50 25 50 (-)
Controls
Beef Master (FM) 49.8 34 25 40 (++)
Better Boy (FM) 37.0 59 40 20 (+)
Early Girl (FM) 36.9 61 40 60 (-)
1 Total yield of 5 plants over 5 picking dates.
2 Quality score is percentage of fruit, by weight, scoring U.S. No.1, size large or above, averaged over two picking dates.
3 EB = early blight with number indicating percent defoliation, PM = powdery mildew with number indicating the percentage of leaves infected, V = tomato mosaic virus, - = none evident, + = on newest growth only, ++ = established infection.

Introduction ! Tree Fruits ! Small Fruits ! Vegetables ! Greenhouse Production ! Diagnostic Laboratory ! Appendix


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