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PR-410: 1998 Fruit and Vegetable Crops Research Report

Vegetables

IntroductionTree FruitsSmall FruitsVegetablesDiagnostic LaboratoryAppendix A

Spring Fresh-market/Slaw Cabbage Cultivar Evaluations in Eastern Kentucky

Terry Jones and Chris Lindon, Department of Horticulture and Landscape Architecture

Kentucky growers produce an estimated 700 acres of spring cabbage for sale to fresh and slaw markets. ‘Bravo’ has been the standard cultivar grown for both markets. It has good hardiness and excellent disease resistance. It produces a head which is fairly large (4-6 lbs), and close spacing must be practiced to permit sales to fresh market. Buyers would like to be able to buy cabbage from Kentucky 10-14 days earlier than our current season in order to fill a market window that exists between the end of harvest in Georgia and the onset of Kentucky sales. Twenty-six cabbage cultivars were evaluated for spring production at the Robinson Experiment Station in Quicksand, Kentucky.

Materials and Methods

Twenty-six cabbage cultivars were seeded on February 10 in a greenhouse at the South Farm in Lexington. They were transplanted at Quicksand on April 7. The trial consisted of a randomized complete-block design with four replications. Each replication was a single row 15 feet long. Plant spacing in row was 12 in. and rows were 36 in. apart. Fifteen plants per rep were used for a total of 45 plants for each cultivar. On April 6, prior to planting, Treflan 2E and Devrinol 50 WP (1 qt + 2 lb) were applied and tilled in for weed control. A 20-20-20 starter fertilizer was used at transplanting. Soil test results for this site are shown in Table 1.

The cabbage was fertilized three times by side dressing as follows: April 13, applied 50 lb N, P, K/acre in the form of 12-12-12; May 6 and May 20, applied 50 lb actual N/acre as ammonium nitrate (NH4NO3.) This represents a total of 150 lb N/acre applied, which is close to our current recommendations for Kentucky.

Results and Discussion

There were many nice-looking cabbage cultivars in this year’s trial. The top five green cultivars (Table 2) were ‘Gideon’, ‘Bronco’, ‘Ramada’, ‘Atlantis’, and ‘Morris’. They produced heads that were harder, more attractive, and better-sized than the industry standard ‘Bravo’. The cabbage cultivars ‘Atlantis’ and ‘Morris’ were earlier than ‘Bravo’ by 8 to 10 days and should be tested further to see if they could be used to expand the market window. They both produced large plants that handled the stress of an excessively wet spring. ‘Atlantis’ produced a slightly larger head than ‘Morris’ (4.2 vs 3.4 lb). These five cultivars are worthy of grower trials to test market acceptability against the grower standards ‘Blue Vantage’ (early) and ‘Bravo’ (late).

‘Gideon’, ‘Bronco’, and ‘Ramada’ matured in the same time frame as ‘Bravo’. They were much harder and had better size control than the ‘Bravo’ grown this year (Tables 2 and 3). During this wet spring, ‘Bravo’ showed some wrapper leaf rot that required peeling, whereas the five cultivars mentioned above did not. Cloudy, extremely wet weather may have delayed the days to harvest by 7-10 days for many of the cabbage cultivars tested. In general, the earliest-maturing cultivars showed the greatest maturity delays. Toward the end of the growing season the weather became very warm, sunny, and dry.

Table 1. Fresh-market cabbage soil test results (lbs/acre).
pHBuf pHPKCaMgZn
6.67.219637975282288.5

Table 2. Yield and quality of spring fresh-market cabbage cultivars, Quicksand, KY; data are means of four replications.
CultivarSeed sourceHead #/acreTotal wt (lb/acre)Avg head wt (lb)Core size (in)Head size LxW (in)Head firmnessaDays to harv.Head shapebInter colorcWt/Crate 14 hd (lb)Plant sized
RatingPenetr. PSI
GideonBZ13552550604.13.97.0 x 6.74.124863-2257.03.0
Worthy of additional trials. Very nice, heavy dome-shaped heads, wavy leaf margins, outer leaves narrow at base don't hold water.
BroncoBZ14036546903.93.86.7 x 6.53.927.8883154.72.2
Worthy of additional trials. Nice, high-domed plant, big core, heads dense but late, outer leaves narrow at base.
RamadaBZ12100474904.03.46.6 x 6.84.025892255.92.4
Worthy of additional trials. Very nice, dense heads, leaves narrow at base, no sunburn or tip burn.
Super RedLI13794427103.12.96.4 x 6.05.028853143.52.1
Commercially acceptable. Very nice, high-domed, dense red cabbage, narrow outer leaf petioles allow water drainage.
AtlantisTI13552555404.13.26.5 x 6.64.223792257.22.8
Worthy of additional trials, nicer than Augusta. No sunburn; long, thin petiole on outer leaves does not hold water, wavy leaf margin, good wrapper cover, no tip burn seen.
MorrisBZ14036451903.23.46.6 x 6.73.422.47322-345.13.0
Worthy of additional trials. Nice, dense heads, larger than Bravo at time of harvest, frame leaves narrow at base.
CharmantLI14036424103.13.45.8 x 6.04.024.3782242.31.5
Heads attractive for small plant, good wrapper leaves, leaves wide at base hold water, a few with rot, no sunburn seen.
Royal VantageRU13068537404.24.17.1 x 6.73.023843-2258.73.4
Leaves wide at base hold water, big core.
Sure VantageRU12826465201.03.76.6 x 6.72.722.3843250.93.6
Outer leaves narrow at base let water drain, some air space in heads where leaves meet stem.
LSD (P = 0.5)51561.22.8
a Rated 1-5 with 1= very loose; 5= very hard; also measured with penetrometer: PSI = lbs/square in.
b Head shape: 1. Flat, 2. Round, 3. High round
c Internal Color: 1. White, 2. Whitish green, 3. Yellowish green, 4. Yellow
d Plant size: 1. Small, 2. Medium 3. Large

Table 3. Yield and quality of spring fresh-market cabbage cultivars, Quicksand, KY; data are means of four replications.
CultivarSeed sourceHead #/acreTotal wt (lb/acre)Avg head wt. (lb)Core size (in)Head size LxW (in)Head firmnessaDays to harv.Head shapebInter colorcWt/Crate 14 hd (lb)Plant sized
RatingPenetr. PSI
CheersTI12342572304.53.86.7 x 7.72.320841-2263.23.4
Worthy of another look. Blue-green, big core, leaves narrow at base excellent drainage, looks nicer than Bravo, but heads did not get hard enough.
FrescoBZ13794605604.43.56.9 x 7.12.921852261.32.7
Blue-green plant, no sunburn on heads, excellent wrapper leaves, but leaves wide at base will hold water; some heads soft/did not harden up.
Green CupTI13794597603.73.06.6 x 7.53.221831-2252.42.1
Average, despite nice appearance in past trials. Blue-green heads, outer leaves wide at base, some heads still loose despite size/did not harden up.
BravoH13068673405.24.07.0 x 7.92.919861-2172.83.0
Industry standard, not the best in this trial for density or appearance. Blue-green heads, leaves medium to wide at base (which holds water). Not all mature at one time/not a real solid cabbage. Some rot on outer wrapper leaves, much too heavy for a 14 count.
Heads UpTI13552438603.24.36.8 x 6.33.019743245.31.9
Garden or farmers' market cultivar but not commercially acceptable. Very uniform maturity, exposed heads (outer leaves do not protect heads), some wrapper sunburn, outer leaves wide at base hold water.
FieldsportBZ13552283702.12.85.7 x 5.24.429733329.71.7
Blue-green plant, too small for commercial market, hard heads but small, outer leaves wide at base could allow rot.
Fast VantageTI14200352502.53.25.6 x 5.62.323672234.81.0
Cute early home garden or farmers' market cultivar. commercially plants too small, outer leaves broad at base.
Blue PakTI12584372703.03.56.0 x 6.24.028782241.52.3
Not commercially acceptable. Nice-looking blue-green cabbage, wide outer leaves hold water, unexplained stunting in one rep.
LSD (P = 0.5)51561.22.8
a Rated 1-5 with 1= very loose; 5= very hard; also measured with penetrometer: PSI = lbs/square in.
b Head shape: 1. Flat, 2. Round, 3. High round
c Internal Color: 1. White, 2. Whitish green, 3. Yellowish green, 4. Yellow
d Plant size: 1. Small, 2. Medium 3. Large

Table 4. Yield and quality of spring fresh-market cabbage cultivars deemed commercially unacceptable, Quicksand, KY; data are means of four replications.
CultivarSeed sourceHead #/acreTotal wt (lb/acre)Avg head wt (lb)Core size (in)Head size LxW (in)Head firmnessaDays to harv.Head shapebInter colorcWt/Crate 14 hd (lb)Plant sized
RatingPenetr. PSI
Blue GemH12826455003.53.45.7 x 6.82.521771-2249.71.9
Big core, leaves broad at base, slightly flattish heads.
DiscoveryRU13794493703.63.96.4 x 6.13.024843249.92.2
Nice-looking blue-green, high-domed cabbage, outer leaves wide to stalk hold water, huge core for head size.
Blue BayouTI11616565104.93.66.2 x 7.73.020841-2268.12.9
Looks nice but tip burn in last rep. Some sunburn on wrapper leaves, leaves wide at base hold water, open space near base of core.
Head StartTI12826503403.94.07.2 x 6.32.018833254.91.6
Sunburn on wrapper leaves, tip burn in heads, large core, wide frame leaves hold water, some head split on last harvested.
PacificaRU12826374502.93.35.9 x 5.73.220782240.81.6
Green plants and heads, too small for commercial use but a cute home garden cultivar. Some leaf sunburn on exposed heads. Heads split when mature, leaves broad at base hold water.
AugustaTI13310613504.64.36.4 x 7.62.721801-2265.02.5
Slight sunburn on heads, tip burn in heads, huge core, wide leaves hold water at base of plant.
CB2TI12826377503.03.76.1 x 5.63.224742242.11.5
Sunburn on heads, wide outer leaves hold water at base, large core (especially for small heads).
Bejo 1772BZ13794732705.43.87.4 x 8.12.920881-2174.63.4
Tip burn, most outer leaves wide at base, air space at base of leaves and core, turns brown quickly when cut, big core.
Supreme VantageTI14036596504.33.87.0 x 6.93.322912260.02.0
Tip burn in every rep., leaves wide at base hold water, some rot on a few heads as a result.
LSD (P = 0.5)51561.22.8
a Rated 1-5 with 1= very loose; 5= very hard; also measured with penetrometer: PSI = lbs/square in.
b Head shape: 1. Flat, 2. Round, 3. High round
c Internal Color: 1. White, 2. Whitish green, 3. Yellowish green, 4. Yellow
d Plant size: 1. Small, 2. Medium 3. Large

Spring Fresh-market/Slaw Cabbage Cultivar Evaluations in Central Kentucky

John Strang, Dave Loury, Dana Hadad, Darrell Slone, and John Snyder, Department of Horticulture and Landscape Architecture; Chuck Owen and Lee Ann Hayes, Bud’s Produce, Elizabethtown

Introduction

Cabbage was evaluated at the University of Kentucky South Farm in Lexington, Kentucky. This study was initiated to select cultivars that mature 7 to 14 days earlier than the industry standard cultivar, ‘Bravo’.

Materials and Methods

Twenty-six cabbage cultivars were planted on February 6 in the greenhouse. Transplants were set on May 14 in a randomized block design with 4 replications. Plots were 15 ft long, and plants were set in double rows with plants spaced 12 in. in the row, with 15 in. between rows on 4 ft centers. There were 30 plants per plot. A 20-20-20 starter solution was used at transplanting. Preplant fertilizer consisted of 140 lb of actual N, P, and K per acre as 19-19-19. Plants were side dressed on June 20 with 100 lb actual N as ammonium nitrate. Command 4EC at 1 pt/acre and Treflan 5E at 2 pt/acre were applied 2 weeks before planting for weed control. Pounce was used for insect control, while Bravo and Kocide were used for disease control. Ten feet of row were harvested in each plot on July 17, 21, and 29. Following harvest, 5 heads of each cultivar were taken to Bud’s Produce in Elizabethtown and evaluated for slaw acceptability and shelf life by Lee Ann Hayes and Chuck Owen.

Results and Discussion

The season was initially very wet, and irrigation was not needed. The top earliest-producing fresh-market cultivars were ‘Blue Vantage’, ‘Atlantis’, ‘Blue Bayou’, ‘Bronco’, and ‘Gideon’. ‘Blue Bayou’ was 7 to 12 days earlier than ‘Bravo’, while the others were 7 to 8 days earlier. The top later-maturing cultivars were ‘Augusta’ and ‘Ramada’. All of these cultivars looked very nice and were firmer and more attractive than ‘Bravo’. All had whitish-green interiors. ‘Super Red 80’ was the only red cultivar, and it also produced very nice heads; however, the internal color was not quite as dark as the industry would like. ‘Blue Vantage’ was the only cultivar that had 18 days of shelf life that slaw processors would like.

Several cultivars appeared to be more sensitive to clomozone (Command) injury than others. The top cultivars, ‘Augusta’, ‘Blue Bayou’, ‘Bronco’, ‘Gideon’, and ‘Super Red 80’ all showed some injury. Although very high tonnages per acre were obtained using double rows, head sizes tended to be on the small side for some cultivars.

Table 1. Yield and head characteristics of fresh-market/slaw cabbage, Lexington, KY, 1998.
CultivarSeed sourceDays to harvestTotal yield (lb/acre)Head (no/acre)Avg. head wt (lb)Core length2 (in) Head size2 L x W (in)Head firmness penetr.3 (PSI)Shape4 (1-3)
MorrisBZ65-7082,791 a121,5083.83.521 x 20192
FrescoBZ69-7070,104 ab18,7853.73.521 x 21172
CheersTI70-7769,968 ab20,6913.43.319 x 20182
Bejo 1772BZ7768,607 ab17,9693.83.120 x 21151,2
Supreme VantageTI65-7066,102 bc20,1473.33.119 x 19201,2,3
Blue VantageAC69-7064,523 bcd21,7803.03.719 x 20192
AugustaTI69-7766,209 bcde21,5082.93.018 x 19202
AtlantisTI69-7060,793 bcde22,0522.83.220 x 18192
Blue GemH69-7060,113 bcde20,6912.03.018 x 1917 1,2
Heads UpTI65-6959,922 bcde19,8743.03.420 x 19212,3
BravoH7759,487 bcde19,3303.13.519 x 21171,2
Blue BayouTI65-7058,888 bcdef19,6023.03.618 x 19191,2
BroncoBZ69-7058,806 bcdef19,8742.93.320 x 18223
Head StartTI6558,234 bcdef20,6912.83.420 x 18232
Green CupTI69-7056,628 bcdef20,4912.82.817 x 19201
PacificaRU6553,415 cdefg16,8803.23.119 x 18182,3
RamadaBZ69-7752,953 cdefg 21,5082.52.417 x 17242
Sure VantageRU69-7052,817 cdefg19,8742.63.719 x 18222,3
FieldsportBZ6950,230 defg21,5082.42.718 x 17232
GideonBZ7040,052 efg19,6022.52.619 x 17203
CharmantLI65-7047,644 efg20,6912.33.117 x 17232
Royal VantageRU65-7044,295 fg19,0582.32.718 x 18212
Fast VantageTI6544,268 fg11,9793.73.120 x 18172
CB2TI65-7043,968 fg19,3302.32.918 x 16233
Blue PakTI69-7043,832 fg19,3302.32.718 x 16262
Super Red 80LI69-7038,578 g22,0521.73.518 x 15243
1Yields followed by the same letter are not significantly different, Waller-Duncan (5%).
2Based on 12 heads.
3Head firmness using a fruit pressure tester, 5/16 in. diameter head, avg. of 12 heads.
4Head shape 1=flat, 2=round, 3=high round.

Table 2. Herbicide injury, head defects, and fresh-market potential of fresh-market/slaw cabbage, Lexington, KY, 1998.
CultivarCommand injury rating1 (1-5)Soft or failed to head (%)Rotten heads (%)Split heads (%)Fresh market potential2 (1-5)Wt/crate 16 heads (lb)
Morris1.403.70--61
Fresco1.14.02.703.859
Cheers2.501.302.554
Bejo 17721.01.51.503.361
Supreme Vantage1.01.301.33.553
Blue Vantage1.44.8001.548
Augusta3.10001.846
Atlantis1.12.41.203.045
Blue Gem3.802.51.32.532
Heads Up1.51.32.55.0--48
Bravo3.51.42.703.350
Blue Bayou2.85.12.603.048
Bronco1.61.31.301.547
Head Start2.0001.3--45
Green Cup1.43.81.302.345
Pacifica1.8011.410.0--51
Ramada1.03.61.202.340
Sure Vantage1.31.31.302.540
Fieldsport1.102.001.538
Gideon1.55.2002.540
Charmant1.004.91.22.037
Royal Vantage1.56.601.34.037
Fast Vantage1.6024.611.6--59
CB21.11.35.21.32.037
Blue Pak1.35.3002.536
Super Red 803.00003.027
1Command injury: 1=none, 5=severe.
2Fresh-market potential: 1=excellent, 5=poor.

Table 3. Processing quality for fresh-market/slaw cabbage and comments, Lexington, KY, 1998.
CultivarQuality 7/241Firmness 7/24Processed QualityComments
6 days211 days218 days2
MorrisGGGGVery uniform & attractive, mild, sweet, several with internal physiological browning at leaf bases, probably B deficiency, adequate leaf cover
FrescoGBBDUniform & attractive, crisp, tender, juicy, mild, core a little dark colored, some stem browning
Cheers--------Uniform in size, attractive, some loose heads, crisp, dry, mild to spicy, good leaf cover
Bejo 1772--------Variable size, attractive, mild, tender, juicy, good leaf cover
Supreme VantageBBGDSome variability in size, attractive, mild, sweet, tender, crisp, some black spots in head
Blue VantageGGGGGVery uniform, attractive, tender, crunchy, juicy, spicy, loose inside, good leaf cover
AugustaGBGDHeads asymmetrical, attractive, crunchy, mild to strong, dry, good wrapper leaves, core slightly yellow
AtlantisGGGDVery uniform, attractive, crunchy, sweet, mild, tender, good leaf cover
Blue GemGBGGVaried size & head shape, attractive, tender, crunchy, spicy, juicy, some tip burn, good wrapper leaves
Heads UpBGGFairly uniform, attractive, juicy, tender, very mild taste
Bravo--------Variable in size, attractive, crisp, dry, mild, tender, some loose heads, good leaf cover
Blue BayouGEGDVery uniform & attractive, very tender, crunchy, mild taste
BroncoGGGBUniform, attractive, mild, juicy to dry, crunchy, good leaf cover
Head StartBGD Variable in size, fairly attractive, mild, sweet, tender, moderate to severe sunburn
Green CupGBGUniform in size, slightly asymmetrical, attractive, short core, crunchy, mild, dry, good leaf cover
Pacifica--------Some variability in size, very attractive, tender, tasty, sweet, splitting problem
RamadaGGGGAttractive, variable in size, mild, crunchy & sweet to spicy, very dense interior, good leaf cover
Sure VantageBBGGVariable in size, asymmetrical, dry, tough, crunchy, mild to spicy, good leaf cover
FieldsportBGMMFairly uniform heads, mild, juicy, sweet, some leaf splitting & spotting, good leaf cover
GideonGBGGVariable size, attractive, tender, crisp, mild, juicy, compact heads, good leaf cover
CharmantGGDVery uniform & attractive, mild, tender, sweet, dry
Royal VantageBBGDVariable in size, attractive, crunchy, slightly tough, dry, mild, dense heads, good leaf cover
Fast VantageBGGGUniform size, not as attractive, tender, sweet, good, some with B deficiency, severe head splitting & severe soft rot losses
CB2BGBDVery variable in size, crisp, mild, dry
Blue PakGGGDVariable in size, attractive, mild, crisp, juicy, tender, good wrapper leaves
Super Red 80GGGDUniform, attractive, very crisp, juicy, mild, slightly sweet, dense heads, good leaf cover, light purple interior
1Quality and cabbage firmness at start of test, 3 days after harvest; E=excellent, G=good, B=bad. Quality based on visual defects. Dashed spaces are where data was lost.
2Processed quality of slaw after storage at 50 F for 6, 11, and 18 days. E=excellent; G=good, still edible; M=marginal; B=bad; D=dump, product severely decayed.

Cabbage Insect Control with a New Insecticide

Ric Bessin, Department of Entomology

Introduction

Imported cabbageworm, cabbage looper, and diamondback moth larvae can be early-season pests of cabbage. These pests can cause serious damage to young transplants as well as causing serious leaf-feeding damage to older plants. Damage to the head or wrapper leaves often reduces marketability. Because many of these pests are much more difficult to control as large larvae, controls will always be most effective when directed toward small larvae. Therefore, early detection of economic infestations is critical to the management of these pests.

Watch for cabbage loopers particularly on the undersides of leaves along leaf margins— but they can be found anywhere on the plant. The larvae are light green, with a pale white stripe along each side. There are three pairs of slender legs near the head and two pairs of club-shaped prolegs toward the other end. Because the larvae have no legs in the middle area of their body, this area arches when the insect moves. All larval stages of the insect move with this looping motion. Large larvae will often curl up and drop down to the base of the plant when the leaf is disturbed. As they grow, they move toward the center of the plant. They generally feed on areas between leaf veins. When scouting, examine the undersides of the lower leaves for newly hatched larvae. Pull back loose wrapper leaves and examine around the base of the head for larger larvae. Evidence of frass at the base of the head aids in the detection of larvae. Because larger loopers are more difficult to control, it is important to time applications for younger larvae.

Diamondback moth larvae, despite their small size, can be very destructive to cole crops. Larvae are small, yellowish-green, spindle shaped, and have a forked tail. When mature, larvae are 5/16 in. in length. Larvae feed on all plant parts but prefer to feed around the bud of young plants. Larvae often drop from the plant on silk threads as soon as the leaf is disturbed. Monitoring should begin when the plants are young. During cupping, larvae that feed on heart leaves are difficult to find unless the outer leaves are pulled back. Heart leaves of preheading plants should be examined if feeding damage is present. Their feeding on the bud may cause malformation of the cabbage head.

Imported cabbageworm larvae are velvety green, with a narrow, light yellow stripe down the middle of the back, and have four pairs of prolegs in addition to the three pairs of legs toward the head. When mature the larvae reach 1 1/4 in. in length. The adult is a white butterfly about 1 3/4 in. long tinged with yellow on the undersides of the wings and black spots on the front wings. Imported cabbageworms cause similar damage to loopers but feed closer to the center of the plant. Large larvae can be particularly damaging to young plants and can cause significant yield reductions. Scouting should begin as soon as the white butterflies are seen flying about during the day.

Materials and Methods

Three insecticides were evaluated for control of diamondback moth, cabbage looper, and imported cabbageworm larvae. The study was located at the University of Kentucky Spindletop Research Farm in Lexington. The test was arranged as a randomized block design with 4 replicates. Individual plots consisted of a single row, 25 ft. long, with 6 ft between rows. Cabbage plants were transplanted on May 19. All insecticide treatments were applied with a CO2 backpack sprayer using 40 psi and 30 gallons finished spray per acre using three TX12 hollow cone nozzles. Insecticides were applied on June 20 and July 1, when larval infestations exceeded 30% of plants infested. On June 19, 23, and 29, and July 5 and 9, the number of larvae were recorded from each of 5 plants per plot.

Results and Discussion

Cool, wet late-spring and early-summer conditions delayed the onset of diamondback moth and imported cabbageworm infestations. All treatments provided significant control of imported cabbageworm for all dates. All treatments provided significant control of diamondback moth larvae for all treatment dates except for the low rate of Spintor on July 29. All treatments provided significant control of cabbage looper on July 5 and 9.

Imported cabbageworm larvae per 5 plants
TreatmentRate/acre19 Jun123 Jun29 Jun5 Jul9 Jul
SpinTor 2SC3 fl. oz.13.3 a0.0 b0.3 b0.0 b0.0 b
SpinTor 2SC6 fl. oz.10.3 a0.0 b0.0 b0.0 b0.0 b
Warrior 1 EC1.96 fl. oz.8.0 a0.0 b0.0 b0.0 b0.3 b
Control8.7 a6.0 a3.0 a4.3 a5.7 a
1Means within the same column followed by the same letter are not significantly different (LSD p>0.05).
Diamondback moth larvae per 5 plants
TreatmentRate/acre19 Jun123 Jun29 Jun5 Jul9 Jul
SpinTor 2SC3 fl. oz.0.0 b0.0 a1.0 ab0.3 b0.0 b
SpinTor 2SC6 fl. oz.3.3 a0.0 b0.0 b0.0 b0.0 b
Warrior 1 EC1.96 fl. oz.6.7 a0.0 b0.0 b0.7 b0.0 b
Control4.0 a5.0 a2.0 a6.3 a5.7 a
1 Means within the same column followed by the same letter are not significantly different (LSD p>0.05).
Cabbage looper larvae per 5 plants
TreatmentRate/acre19 Jun123 Jun29 Jun5 Jul9 Jul
SpinTor 2SC3 fl. oz.0.0 a0.7 a3.0 a0.3 b0.7 b
SpinTor 2SC6 fl. oz.0.0 a0.0 a1.3 a0.0 b0.3 b
Warrior 1 EC1.96 fl. oz.0.0 a0.0 a1.3 a0.3 b0.7 b
Control0.0 a1.3 a7.3 a4.7 a4.0 a
1 Means within the same column followed by the same letter are not significantly different (LSD p>0.05).

Sugar Enhanced, Everlasting Heritage (E.H.), Sweet Breed, and Sweet Gene Corn Evaluations in Central Kentucky

John Strang, Dave Loury, Dana Hadad, Janet Pfeiffer, and Darrell Slone, Department of Horticulture and Landscape Architecture

Sweet corn cultivars were evaluated at the University of Kentucky South Farm in Lexington.

Materials and Methods

Twenty-eight sugar enhanced (se), 1 sweet gene, and 2 E.H. varieties were planted by hand on June 27, 1998. Plots consisted of a 20-ft long row of each cultivar replicated four times. Rows were spaced 3.5 ft apart, and 100 seeds were planted in each 20-ft row. Plants were thinned to a distance of 8 in. apart following emergence. Prior to planting, 138 lb of actual N, P, and K were applied as 19-19-19 and tilled in. Plants were side dressed with 20 lb of actual N as ammonium nitrate. Three quarts of Lasso 4E and 2 lb of Bladex 90 DF per acre were applied preemergence, and 1 qt of Atrazine 4L was applied on July 2 for weed control. Warrior and Sevin were used for insect control.

Results and Discussion

The season was initially very wet and then turned very dry. The plot was not irrigated, so some butt end blanking was noted, and obtaining good tip fill was more difficult, particularly on later-maturing varieties. Cultivars that were the better performers in this trial should perform well under hot, dry conditions. Seneca Sensation, Divinity, Silver Princess, Immaculata, Sweet Ice, and Argent were the better-performing white varieties. Kandy Plus, Sugar Ace, Tuxedo, GH-4881, and Legend were the best-performing yellow varieties. Sugar Ace, a sweet gene variety, had the best husk coverage and tip fill in the trial. GH-4881 was rated as being the best-tasting variety. Jackpot was the best of the two bicolor varieties, although this trial was initially designed to evaluate just yellow and white varieties. Ruby Queen is a new orange se variety that was released this year. There were not enough seed to give this a fair test for yield; however, it did not color up as expected, and there was quite a bit of variation in color intensity from ear to ear.

Table 1. Plant characteristics and yield of sugar-enhanced, E.H., sweet breed, and sweet gene corn cultivars, Lexington, 1998.
CultivarSeed sourceDays to maturityPlant stand1 (%)Seedling vigor2 (1-5)Seedling uniformity3 (1-5)Height to first harvested ear (in.)Ease of ear harvest4 (1-5)Yield (dozen ears per acre)
Seneca SensationSW739043.8193.51737
DivinityST78843.83.5163.11737
Silver PrincessRG, ST, SW757943.3183.31698
ImmaculataST, SW78864.54.0163.31608
Kandy King E.H.RG73872.83.0152.91608
Kandy PlusRG79802.32.3222.81582
Sugar Ace (sweet gene)H79844.03.5202.61530
TuxedoSW78863.82.5163.41530
Sweet Ice (sweet breed)H74744.03.0183.51517
WHT-2972RG67914.84.5153.41452
Seneca DaybreakN64763.82.8153.51426
Kandy Korn E.H.BU, SW, TR89843.83.0263.61413
BrillianceH79883.52.8183.41387
GH-4881RG79732.83.0212.11361
IncredibleSW85722.82.0223.81335
LegendH73733.52.8143.61322
MiracleTR, N84702.52.3164.01296
ArgentST, SW83733.52.8213.41296
King Arthur'sST66-73853.53.0183.91258
Silver KingH, RG, ST, SW82682.82.0243.61245
JackpotRG82823.02.8202.41245
Sugar Snow IIPA, ST 66-74853.83.3123.41219
BC-4885RG82782.82.8203.31193
Silver ChoiceBU, SW75803.02.3183.91128
Spring TreatSW68752.82.0123.81076
Star DustPA70532.82.0143.61037
Sweet N' SlimBU74612.02.0183.3 998
Spring SnowH66753.02.5144.0 920
Early ChoiceBU, SW65843.83.0133.5 869
Seneca StarshineTR75-85331.31.5143.4 700
Ruby QueenBU75121.51.5164.2 480
1Plant stand is percent emergence based on planting 100 seeds.
2Seedling vigor: 1 = poor, 5 = excellent.
3Seedling uniformity: 1 = poor, 5 = excellent.
4Ease of harvest: 1 = hard, 5 = easy.

Table 2. Ear characteristics of sugar-enhanced, E.H., sweet breed, and sweet gene corn, Lexington, 1998.
CultivarHusk coverage1 (1-10)Ear length (in)Ear width (in)Tip fill2 (1-10)Row straightness3 (1-10)
Seneca Sensation9 7.11.82.85.3
Divinity9.5 7.41.77 7.3
Silver Princess8 7.41.96.57.3
Immaculata9.8 7.11.88 7.0
Kandy King E.H.5.3 7.41.83 6.0
Kandy Plus7.5 8.21.95 6.0
Sugar Ace (sweet gene)10.07.61.79.58.0
Tuxedo7.0 7.91.77.08.0
Sweet Ice (sweet breed)9.0 7.57.58.56.7
WHT - 29720 6.71.95.75.3
Seneca Daybreak0 7.31.93.08.0
Kandy Korn E.H.2.3 8.31.70 7.0
Brilliance4.5 8.31.85.86.8
GH-48818.3 8.01.83.06.0
Incredible5.3 7.81.94.06.0
Legend8.3 7.01.88.05.5
Miracle4.5 8.11.83.08.0
Argent9.5 7.81.73.07.5
King Arthur's2.5 6.91.93.05.0
Silver King4.0 7.71.84.85.5
Jackpot8.0 8.01.82.86.3
Sugar Snow II4.3 6.61.82.55.3
BC-48858.3 7.91.83.36.3
Silver Choice6.3 7.51.76.86.0
Spring Treat2.8 6.91.85.06.0
Star Dust5.0 6.91.88.03.7
Sweet N' Slim8.5 7.21.49.06.0
Spring Snow3.3 6.31.73.05.0
Early Choice1.3 6.71.74.05.0
Seneca Starshine6.5 6.51.76.37.5
Ruby Queen5.8 6.41.76.34.5
1Number of ears out of 10 that had tight husk coverage over the ear tip.
2Number of ears out of 10 that had good tip fill.
3Number of ears out of 10 that had straight rows of kernels.

Table 3. Ear quality characteristics of sugar-enhanced, E.H., sweet breed, and sweet gene corn cultivars, Lexington, 1998.
CultivarCooked CornComments
Pericarp tenderness1 (1-4)Kernel tenderness2 (1-4)Sweetness3 (1-4)Kernel color4
Seneca Sensation2.53.03.5WVery attractive ear
Divinity3.53.53.5WAttractive ear, excellent husk coverage, long flags, some butt end blanking
Silver Princess2.53.03.0WAttractive husk & ear, ear snaps easily from husk, some bird damage
Immaculata3.53.53.0WAttractive ear, excellent husk coverage, long flags, shuck snaps off easily, slight smut
Kandy King E.H.3.53.53.5YAttractive ear, shuck snaps off easily, some butt end blanking, some bird damage
Kandy Plus4.03.53.5YAttractive husk & ear, butt end blanking
Sugar Ace (sweet gene)3.03.53.5YAttractive husk, very tight husk coverage, some butt end blanking
Tuxedo3.04.03.0YAttractive husk & ear, some butt end blanking, bird & raccoon damage
Sweet Ice (sweet breed)2.03.03.0WVery attractive husk & ear, long flags, some butt end blanking
WHT - 2972------WSevere bird & raccoon damage
Seneca Daybreak2.52.02.5YSevere bird & raccoon damage
Kandy Korn E.H.4.03.52.5YBurgundy-colored husk, attractive ear, some butt end blanking
Brilliance3.53.02.5WVery attractive husk & ear, long flags, some butt end blanking
GH-48814.04.04.0YVery attractive ear
Incredible4.03.53.0YAttractive ear & dark green husk, short flags, some butt end blanking
Legend2.53.03.0YAttractive husk & ear, some ears w/tassels, slight bird damage
Miracle4.03.53.0YAttractive husk & ear
Argent3.53.53.5WAttractive husk & ear, long flags
King Arthur's3.54.03.5YDeep, tender kernels; bird & raccoon damage
Silver King3.53.03.0WVery attractive ear, some butt end blanking
Jackpot4.03.53.5BCAttractive husk & ear, short flags, butt end blanking
Sugar Snow II3.03.53.5WSevere bird & raccoon damage
BC-48853.03.53.0BCAttractive ear, small kernels
Silver Choice3.53.53.5WAttractive ear
Spring Treat3.03.02.5YSevere bird & raccoon damage
Star Dust------WSevere bird & raccoon damage
Sweet N' Slim3.03.03.0YAttractive long, slim husk & ear; 12 rows of kernels
Spring Snow3.03.53.0WAttractive ear, dark green husk, severe bird & raccoon damage
Early Choice3.53.02.5YSevere bird & raccoon damage
Seneca Starshine3.03.02.5WSevere bird & raccoon damage
Ruby Queen3.53.03.0OOrange color did not develop well
11 = tough, 4 = tender.
21 = crisp, 4 = creamy and tender.
31 = starchy, 4 = very sweet, ratings are based on one ear.
4Y = yellow, W = white, BC = bicolor, O = orange.

Sweet Corn Insect Control

Ric Bessin, Department of Entomology

Introduction

Consumer demand for damage-free sweet corn means that growers must develop the best possible management program for insect pests, especially those that attack the ear. European corn borer populations fluctuate from year to year and can be more severe in some fields than others. There are two generations of this insect each year. The first generation occurs from early June to early July and is most damaging to early-planted corn. The second generation in August and September is a greater threat to sweet corn. Borers of this generation attack the ears and ear shanks.

The corn earworm is the most serious sweet corn pest because it feeds directly on the ear tips. Once worms have become established within the ear, control is impossible. Earworms are variable in color but have a brown head without markings and numerous microscopic spines covering their body. Earworms spend a relatively short period of their life feeding in a site that can receive an adequate insecticide application. A preventive program, especially on late-season corn, is necessary to ensure that damaged ears are at a minimum.

Infestations of fall armyworm are most likely to occur on corn that is knee to waist high in July. Late-planted sweet corn, especially in the southern tiers of counties, should be watched closely for fall armyworm activity. The larvae or worms feed on leaves and in the whorl. They will enter the ear and cause damage similar to that from the corn earworm.

Materials and Methods

Nine insecticide treatments were evaluated for control of insects attacking sweet corn ears. The test plot was planted in a 4th-year corn field on the UK Spindletop Research Farm in Fayette County on June 22 as a randomized block design with 3 replicates. All plots received Bicep 6L at 2.4 quarts per acre and Roundup 3L at 2 pints/acre at planting. Individual plots consisted of four rows, 75 feet long with 36-inch row spacing. Insecticides were applied using a CO2 backpack sprayer using 40 PSI and 23 gallons finished spray per acre. Insecticide applications were made on July 25 and 30 and August 4 and 11; however, some treatments were only applied on the first two application dates. Fifty ears per plot were examined for damage by European corn borer, corn earworm, and fall armyworm on August 19 and 20.

Results and Discussion

All treatments significantly reduced the number of European corn borer- and corn earworm-damaged ears. In general, corn earworm levels were low at this point in the season, possibly due to cool early-summer temperatures. All treatments increased the number of clean ears relative to the control.

Application1Percentage of damaged ears2
TreatmentRate / acreDatesECBCEWFAWClean
Control----47.3 a13.3 a14.0 a34.7 b
Baythroid 2 EC2.0 fl oz1,2,3,43.6 b2.1 b3.7 b90.6 a
Baythroid 2 EC2.5 fl oz1,2,3,40.7 b1.3 b4.7 b93.3 a
Baythroid 2 EC2.5 fl oz1,24.0 b3.3 b4.0 b88.7 a
Pounce 3.2 EC8 fl oz1,2,3,40.7 b0.7 b1.3 b97.3 a
Pounce 3.2 EC8 fl oz1,23.3 b2.7 b2.0 b92.0 a
Warrior 1 EC2.56 fl oz1,2,3,40.0 b0.0 b2.0 b97.3 a
Warrior 1 EC3.2 fl oz1,2,3,42.0 b 1.3 b6.0 b90.7 a
Warrior 1 EC3.2 fl oz1,23.3 b3.3 b5.3 b88.0 a
Warrior T 1CS3.2 fl oz1,2,3,40.0 b2.0 b0.0 b97.3 a
1Application dates: 25 Jul (1), 30 Jul (2), 4 Aug (3), and 11 Aug (4).
2Means in the same column followed by the same letter are not significantly different (LSD: p < 0.05).

Pumpkin Cultivar Trial

Terry Jones and Chris Lindon, Department of Horticulture & Landscape Architecture

Introduction

As a fall crop, pumpkins allow Kentucky growers to extend their marketing season and take advantage of labor used to cut and house tobacco. Both wholesale and direct-market pumpkin acreage has increased dramatically during the past five years. ‘Howden’ has been the predominant cultivar grown for jack-o-lantern sales. However, problems with fruit set during high temperatures and Fusarium fruit rot have created a need for better cultivars. As a result, a pumpkin cultivar trial was conducted at the University of Kentucky’s Robinson Experiment Station in Quicksand, Kentucky. Seventeen cultivars, six of which were small or miniature pumpkins, were evaluated in 1998.

Materials and Methods

Lime at the rate of 2 tons/acre was applied to the planting site in May and tilled in (Table 1). Seeds were planted directly in the field on June 17. Each cultivar was replicated three times in a randomized complete block design. Each replication consisted of a single row 30 ft long containing 12 plants (2/hill). Seeds were hand sown 5 ft apart in the row with 14 ft between rows.

Fifty lb/acre of N, P, and K (19-19-19) were applied as a side dressing 2 weeks after planting. A final side dressing of ammonium nitrate was applied at the rate of 100 lb actual N/acre when the vines began to run (July 16). Thus, a total of 150 lb of actual N was applied during the growing season. Curbit EC at 4 pt/acre was applied after planting on 6/22/98. Four preventative sprays containing Thiodan or Pounce and Bravo or Bravo plus Benlate were applied during the growing season for disease and insect control as conditions warranted. Irrigation was applied once during the growing season. Growing conditions went from cool and excessively wet in the spring to hot and very dry in August.

Results and Discussion

The two best-looking large jack-o-lantern pumpkins in the trial were ‘Pro Gold 510’ and ‘Gold Strike’. They produced good yields of 20-pound pumpkins that were blocky and dark orange in color with excellent stems (Table 2). ‘Appalachian’ also gave acceptable yields of large, attractive fruit, but it was not as attractive as ‘Pro Gold 510’ or ‘Gold Strike’. For the first time in several years at Quicksand, ‘Howden’, the industry standard, also did very well. Because of excessively wet weather in late May and early June, the intended planting time was delayed 10 to 14 days. Planting this late may have hurt the yield of ‘Gold Rush’, which is a 120-day pumpkin. It was very hot and dry by the time ‘Gold Rush’ began fruiting.

Among the small decorative pumpkins, ‘Baby Bear’ and RWS 6260 gave the best yields of attractive small fruit (Table 3). ‘Peek-A-Boo’ and ‘Hybrid Pam’ had attractive fruit, but their yields were lower than desired. ‘Big Autumn’ (Table 2) gave high yields of a very uniform mid-sized pumpkin that would be well suited for school children who might not be able to pick up the larger-fruited pumpkin cultivars. ‘Wee-Be-Little’ was a very attractive, dark orange small pumpkin. As a bush-type plant, a closer row spacing might improve its yields. Additional testing of this cultivar is necessary. ‘Sweetie Pie’ gave nice-sized fruit, but they were a very pale yellowish orange, which we feel caused them to be less attractive.

Table 1. Pumpkin Cultivar Soil Test, Quicksand, KY. (lb/acre).
pHBuf-pHPKCaMgZn
5.06.51673641752755.2

Table 2. Yield and quality of standard size pumpkin cultivars, Quicksand, KY; data are means of three replications.
CultivarSeed SourceNumber/acreCwt./acreAvg Wt. (lb)ShapeaSmoothnessbRibbingcColordStem QualityeStem Colorf
Gold RushRUP1,52037324.623.02.8MO3.5dg
Huge stem looked best on highest ground, not planted quite early enough due to wet weather.
Mother LodeRUP1,86735419.023.53.2MO3dg
Fair appearance, a few green fruit, occasionally one rotted.
Gold StrikeRUP2,45452121.222.83.2DO3dg
Very nice large pumpkin! Attractive stem.
HowdenTV2,48943517.522.73.0DO3dg
Nice looking pumpkins.
Pro Gold 510RUP2,95968923.323.03.0DO3dg
Very nice looking pumpkins.
TallmanST176330717.422.72.5MO3dg
Variable fruit size, not as attractive as some.
Early AutumnRG3,04244714.724.04.0MO2.7dg
Nice, very uniform pumpkin, yellow band around stem base.
Big AutumnRG3,90663516.224.03.5MO3dg
Very nice uniform fruit, yellow ring around stem base, nicer than Early Autumn.
Jumpin JackRUP2,28247020.623.33.0DO3dg
Fairly attractive, some fruit still green.
AppalachianPS2,31645719.723.02.8DO3dg
Attractive large pumpkin.
TraxSW197043121.922.02.8MO3dg
Uneven fruit size and shape, not as attractive as most of the others.
LSD (P = 0.05)ns632.50.12
a1 = oblate or flat, 2 = blocky, 3 = round
b1 = rough warty skin, 5 = very smooth
c1 = heavy ribbed, 5 = no ribbing smooth
dlo = light orange, mo = medium orange, do = dark orange, ro = reddish orange, w = white
e1 = weak, small breaks off; 3 = strong and large
flg = light green, mg medium green, dg = dark green, t = tan

Table 3. Yield and quality of small/miniature pumpkin cultivars, Quicksand, KY; data are means of three replications.
CultivarSeed SourceaNumber/acreCwt./acreAvg Wt. (lb)ShapebSmoothnesscRibbingdColoreStem QualityfStem Colorg
Baby BearRUP11,0971631.5133DO3dg
Very attractive, small, flattish pumpkin.
Sweetie PieST18,4257300.4132.8LO3dg
Pale yellowish orange fruit, wish they were darker.
Peek-A-BooRG4,4591533.4233MO3dg
Nice looking small pumpkin, yield only fair.
Wee-Be- LittleRG7,726460.6144.5DO3dg
Bush type plant, nice small pumpkin but yield at this spacing not high.
RWS 6260RG8,0541742.2233DO3dg
Very nice small pumpkin!
Hybrid PamSW2,212994.5233MO3.5dg
Very nice looking small pumpkin with a huge stem for size, but not a high yield.
LSD (P = 0.05)2631633.50.12
a1= oblate or flat, 2 = blocky, 3 = round
b1 = rough warty skin, 5 = very smooth
c1 = heavy ribbed, 5 = no ribbing smooth
d lo = light orange, mo = medium orange, do = dark orange, ro = reddish orange, w = white
e:1 = weak, small breaks off; 3 = strong and large
flg = light green, mg medium green, dg = dark green, t = tan

Powdery Mildew Resistant Pumpkin Cultivar Observation Trial

John Strang and John Hartman*, Department of Horticulture and Landscape Architecture and *Department of Plant Pathology; Dale DePoyster, Big Clifty

Powdery mildew resistant pumpkin cultivars and breeding lines were evaluated at Dale DePoyster’s farm in Big Clifty.

Materials and Methods

Nine powdery mildew resistant pumpkin cultivars and breeding lines from Harris Moran Seed Company were planted on July 20, 1998, in a nonreplicated observation trial. Twenty seeds of each cultivar were planted to make a 40-ft-long row of each cultivar. Seeds were spaced 2 ft apart on 12-ft row centers. No herbicides or fungicides were used. Insecticides were used only until early August.

Results and Discussion

Atlantic Giant, HMX 6687, and HMX 8691 had the lowest plant powdery mildew incidence. Both of these numbered lines had very nice fruit quality. HMX 6689 had the highest yield and produced nice-quality pumpkins. HMX 8696 was the lowest-yielding line but produced very attractive, small 5-6 in. diameter pumpkins. The other small pumpkin, HMX 6688, contained a large number of fruit that had not colored up completely at harvest. However, these colored up after harvest and were very nice.

Only two lines, HMX 8694 and HMX 8692, were judged to be less desirable due to stem decay problems, and these had the highest incidence of powdery mildew in the study. Most cultivars had very dark orange fruit that was quite attractive. One advantage of most of these cultivars was that the powdery mildew resistance helped to improve stem quality, and the stems held up very well after harvest.

This trial was planted very late in the season because the seed had not been available earlier. Late-summer dry weather probably reduced fruit size, because the plot was not irrigated. Unfortunately, a powdery mildew susceptible cultivar was not included in this plot, so it is difficult to determine the extent of resistance in these new breeding lines and/or cultivars.

Table 1. Powdery mildew resistant pumpkin cultivar observation yield and fruit characteristics, Big Clifty, 1998.
CultivarYield (T/A)Fruit (no/A)Avg. fruit wt. (lb)Fruit length (in)1Fruit width (in)Fruit shapeFruit smoothness2 (1-5)Fruit ribbing3 (1-5)Fruit colorStem quality (1-3)4 Overall looks5 (1-5)
HMX 6689 16.03,2679.98.88.3slightly elongated33v. dark orange2.53
HMX 869412.02,360 10.610.08.5elongated3.53 light orange1.52
HMX 668711.01,997 10.48.78.5round 32 v. dark orange2.54
HMX 869210.93,2676.79.08.0round 3 2.5 dark orange2.52.5
Magic Lantern HMX 568310.02,360 8.39.28.5round & elongated 2 2dark. orange2.54.5
HMX 86919.53,086 6.28.77.5elongated 3 2 dark orange2.53.5
HMX 6688 6.12,904 4.2 5.8 6.3round 2 2v. dark orange3.04
HMX 86965.52,541 4.3 5.8 6.5flat to round 4 4v. dark orange3.04.5
1Fruit measurements based on 3 fruit.
2Smoothness: 1=rough, 5=smooth.
3Ribbing: 1=heavily ribbed, 5=smooth.
4Stem quality: 1=weak, small breaks off, 3=strong and large.
5Overall looks: 1=poor, 5=excellent.

Table 2. Pumpkin cultivar powdery mildew incidence and comments, 1998.
CultivarPM overall incidence 9/24 (%)PM severity 9/24 (%)PM rating 9/241 (%)PM overall incidence 10/16 (%)PM severity 10/16 (%)PM rating 10/161 (%)PM stem rating2 (1-5)Comments
HMX 66898020169590862.0Attractive, slight variation in size, light to dark green stem, small vine
HMX 8694301039595903.0Stem decay problems, lighter weight fruit, tan to dark green stem, small vine
HMX 6687 5 50.35020101.5Attractive, fairly uniform fruit size, dark green stems, large vine
HMX 86929050459595902.5Attractive, variable in size, tan to dark green stems, small vine
Magic Lantern HMX 56836040247075531.5Variable in shape and size, dark green stems, large vine
HMX 869150 52.57520152.0Attractive, some variation in size, medium to dark green stems, large vine
HMX 66886040249085772.0Most fruit still somewhat green at harvest, large light to dark green stems, large vine, small pumpkin
HMX 8696501059080721.5Attractive fairly uniform small pumpkin, dark green stems, small vine
Atlantic Giant 5 50.31510 21.0
1Powdery mildew rating is percent overall powdery mildew incidence on the plant X percent powdery mildew severity on the plant.
2Powdery mildew stem rating: 1=0 incidence, 3=50 percent brown and shriveled, 5=100 percent brown and shriveled.

Orange and Purple Pepper Cultivar Trials

John Strang, Dave Loury, Larry Swartz, Janet Pfeiffer, Darrell Slone, and John Snyder, Department of Horticulture and Landscape Architecture; Dan Moore and Mike Klahr, Hebron and Burlington

Orange and purple pepper cultivars were evaluated at the University of Kentucky South Farm in Lexington, Kentucky, and on Dan Moore’s farm in Hebron.

Materials and Methods

Six orange and six purple pepper cultivars were seeded in the greenhouse and transplanted to the field on May 19 in a randomized block design. All plants were set on raised beds, covered with black plastic mulch, and trickle irrigated. Individual treatments were 12 ft long, and plants were set in double rows with plants spaced 12 in. apart in the row with 15 in. between rows on 6-ft row centers. Preplant fertilizer consisted of 230 lb of actual N, P, and K as 19-19-19. Plants were fertigated with 2.3 lb of actual N/acre as ammonium nitrate on July 9 and June 10 and 18. Dual 8E at 1.5 pt/acre was applied to the unmulched area of the field following transplanting. Asana, Pounce, and Orthene were used for insect control, and Kocide was used for disease control. Peppers were harvested on July 27, August 14 and 27, September 9, and October 10 and graded into extra large, large, medium, small, and cull categories. Plants were transplanted on May 28 on Dan Moore’s farm in a sandy soil along the Ohio River. No herbicide was used, and the planting was sidedressed and irrigated twice. The purpose of this portion of the study was to assess cultivar marketability in a direct-marketing situation.

Results and Discussion

Lexington

Mandarin, a long, very large, European-type pepper, was the best of the dark orange cultivars, although it was relatively susceptible to Alternaria. Valencia was the best dark orange blocky bell pepper, while Oriole was the best light orange cultivar. All of the orange varieties were very juicy and sweet when ripe.

Lilac was the best lavender-colored purple pepper, while Purple Beauty was the best dark purple pepper. Purple peppers are picked in an immature state, and the skin of all the cultivars tended to be tough and the fruit slightly bitter. It was very difficult to harvest these varieties in the purple state and hard to get good size during hot weather. The tendency was to wait for a better purple color to develop; however, by then they had started turning orange and red. A number of these varieties changed to orange and red very quickly during hot weather, and individual fruits were often purple, orange, and red at the same time. Sunburn was a problem on most of the cultivars in August.

Hebron

Dan Moore rated Mandarin as the best orange pepper and Purple Pepper as the best purple. Purple Pepper was slightly better than Blue Jay, although both sold very well. He felt that Purple Beauty was very good for an open-pollinated variety. Dan will raise Mandarin, Purple Pepper, Blue Jay, and Purple Beauty again and may look at Lilac and Bendigo.
Table 1. Orange and purple bell pepper yields and fruit characteristics, Lexington, 1998.
CultivarSeed sourceColorDays to harvestTotal X-large1 (lb./A)Total X-large (no/A)Total X-large + large 2 (lb./A)Total X-large + large (no/A)Avg. wt/fruit X-large + large (lb)Total mkt. (lb)Fruit lobes (no.)
Purple PepperJSpurple6026,31855,028 37,754 a92,220.4143,7134
MavrasEZpurple7424,83951,983 36,616 ab89,610.4141,3143-4
OrioleSTorange7414,61631,103 29,602 abc69,818.4330,9724
Blue JaySTlilac73 4,43710,875 29,167 abc88,958.3340,7603
Purple BeautyPKpurple7419,90142,630 29,145 abc72,645.4035,1263-4
BendigoEZorange74 4,15410,005 29,905 abc78,083.3433,6473-4
MandarinRGorange74-78 16,72630,668 26,687 abcd53,940.5027,5793-4
ValenciaJS, RG, SWorange68-7222,40348,720 25,709 abcd60,248.4326,3184
QueenEZorange6817,29137,845 24,578 cd60,248.4125,4913
LilacPK, RG,SWlavender68 5,91613,050 23,882 cd61,770.3938,0843-4
LavenderJSlavender56 3,110 7,830 23,816 cd70,253.3438,1284
Orange GrandeSTorange7611,00623,708 16,922 d41,108.4117,6614
1Extra large >3.5 in. diam.; large 3-3.5 in. diam.; medium 2.5-3 in. diam.
2Yields followed by the same letter are not significantly different by Waller-Duncan (5%).

Table 2. Orange and purple bell pepper fruit characteristics and comments, Lexington, 1998.
CultivarOverall appr.1 (1-5)Color quality1 (1-5)Decay rating 8/141 (1-5)Color changeComments
Purple Pepper2.33.12.6green - purple - redVery large blocky fruit, purple-green color, turn red too rapidly, some asymmetrical & multi-lobed
Mavras2.83.32.5green - purple - redBlocky, some flat and malformed, shape not good, not a good purple, turn red too rapidly,
Oriole4.34.52.1green - lt. orangeNice uniform orange color, very attractive, color & blocky shape hold up all season
Blue Jay2.82.82.4lilac - grape - orange - redSmaller size, multicolored fruit, nice red when mature, some scarf skin & shoulder cracking
Purple Beauty3.03.52.1green - dark purple - redDark purple has green in it, turns red quickly, irregular shape
Bendigo3.43.02.3green - reddish orange - redSmaller size, orange-red color turns red quickly, looks more red than orange
Mandarin3.83.43.4green - dark. orangeLarge & very long, very attractive dark orange, takes longer to color up, Alternaria rot is a problem
Valencia3.74.02.5green - dark. orangeNice dark orange, very attractive, some variation in shape
Queen3.83.83.3green - yellow - lt. orangeBlocky shape that held up over the season, some with multiple lobes, Alternaria susceptibility
Lilac3.23.42.4lavender - redShort, blocky shape, best lilac color, very attractive, turns red quickly
Lavender3.13.13.3lavender - orange - redBlocky small fruit, many fruit multicolored, some scarf skin & shoulder cracking
Orange Grande3.84.23.4green - lt. orangeAttractive, blocky large fruit, Alternaria susceptibility
1Overall appearance, color quality, and decay rating: 1=poor, 5=excellent.

Table 3. Orange and purple pepper quality, marketability, and yield rating, Dan Moore's farm, Hebron,1998.
CultivarQuality1 (1-5)Marketability1 (1-5)Packout1 (1-5)Field yield1 (1-5)Comments
Mandarin4545Very large; excellent yield; tendency to rot on plants, sometimes before they turn color
Orange Grande4544
Bendigo4444Many large peppers in center of plant at 1st harvest, best foliage protection from sunburn
Oriole3333
Valencia3422
Queen2332
Purple Beauty4443Dark purple color & best taste of any red pepper, thick walls
Blue Jay4544Good seller
Purple Pepper4544A little better than Blue Jay, good seller
Lavender3332
Lilac3433
Mavras3122Did not sell well at brownish green stage
1Rating system: 1=poor, 2=fair, 3=good, 4=very good, 5=excellent.

Evaluation of Newly Registered Insecticides for European Corn Borer Control on Bell Pepper

Ric Bessin, Department of Entomology

Introduction

European corn borer remains the key insect pest attacking peppers in Kentucky. European corn borer can cause severe damage to peppers in commercial fields throughout Kentucky. Feeding by corn borer larvae can cause several problems, the most serious of which is direct damage to the fruit and premature drop of small fruit. Borer entrance holes in larger pods allow water to enter, resulting in fruit rot. When rotting begins, borers often leave and move to infest new fruit. In this way, one larva can damage several pods. In addition, plants may break due to tunneling by the borers in the stems.

European corn borer moths tend to congregate in tall grassy areas around field margins, called action sites. Females fly into fields at night to lay their eggs. Weather conditions during egg laying can greatly affect the severity of corn borer problems. Calm, warm nights are most favorable for moth activity, while few eggs are laid on windy, stormy nights.

European corn borer eggs are laid in masses of 15 to 30 eggs. Eggs are round and flattened and overlap each other like fish scales. Often they are placed on the underside of the pepper leaf near the midrib. Age of the egg mass is indicated by its color: freshly laid eggs are white, then cream. When a distinct black spot (the head of the larva) can be seen in the egg, it will hatch in about 24 hours.

Newly hatched larvae, about 1/16 in. long, leave the mass and crawl toward the developing pods. They do little feeding on pepper leaves. Within 2 to 24 hours after hatching, young larvae reach the calyx of the pepper pods. Once under the calyx, they are protected from insecticides and natural enemies.

There are two to three generations of this pest each year. The first appears in late May through early June. The second generation develops from late July through August. A partial third generation may occur in some years in early September. The second, or midsummer generation, is most likely to cause problems for commercial pepper producers.

Materials and Methods

Three insecticide treatments were evaluated for control of European corn borer insects attacking bell pepper. ‘California Wonder’ pepper plants were transplanted on the UK Spindletop Research Farm in Fayette County on May 19 as a randomized block design with 4 replicates. Individual plots consisted of single rows, 23 ft long, with plants spaced 20 in. apart in the rows. All insecticides were applied using CO2 backpack sprayers with drop nozzles using 40 PSI and 30 gallons finished spray per acre. Insecticide applications were made on 5, 13, 20, and 27 Aug. On Sept 1, all the mature fruit in each plot were removed and examined for damage by European corn borer.

Results and Discussion

European corn borer pressure was high during the course of this study, and the initial sprays were applied after some of the larvae had already penetrated into the fruit. Because of this, the damage observed in the Warrior and Spintor treatments is likely to be higher than would be expected in a commercial situation. The Warrior 1 EC and the Spintor 2SC at 6 fl oz per acre significantly reduced the number of European corn borer-damaged fruit. However, the low rate of Spintor was not significantly different from the control.

Treatment1Rate / acrePercentage of ECB damage2Total fruit2
Spintor 2 SC3 fl oz26.6 ab63.8 a
Spintor 2 SC6 fl oz14.8 b62.5 a
Warrior 1 EC1.96 fl oz14.0 b70.3 a
Control--37.7 a62.0 a
1 Application dates: 5, 13, 20, and 27 Aug.
2 Means in the same column followed by the same letter are not significantly different (LSD: p < 0.05).

Yield, Disease Resistance, and Quality of Staked Tomato Cultivars

Brent Rowell, R. Terry Jones, William Nesmith*, John C. Snyder, and Janet Pfeiffer, Department of Horticulture and Landscape Architecture and *Department of Plant Pathology

Introduction

Kentucky growers currently produce about 1,200 acres of staked, vine-ripened tomatoes for both local and national markets. Kentucky tomatoes have an excellent reputation for quality in some market areas like Chicago. Merchandising managers at the Kentucky Distribution Center of the Kroger Company (serves 100 supermarkets in Kentucky, Illinois, and West Virginia) expressed a strong interest and commitment to marketing local produce in general and Kentucky tomatoes in particular. We began fresh-market tomato trials in 1998 in order to evaluate new commercial cultivars and to identify a variety which might be featured in supermarkets as a premium “Kentucky Tomato.” We evaluated new varieties for yields and quality and compared them with established commercial varieties such as ‘Mountain Spring’ and ‘Mountain Fresh’. We were looking specifically for the following characteristics in the “Kentucky Tomato” variety:

  1. Large slicer that tastes good
  2. Ships well (firm, but not necessarily the most firm among cultivars)
  3. High yields of extra-large and larger fruit
  4. Reasonably free from defects

Materials and Methods

A carefully selected group of 16 determinate tomato varieties from four seed companies was evaluated at two locations in Kentucky. All trial entries for both locations were seeded in the greenhouse at the South Farm in Lexington (LEX) on March 3 and transferred to 72-cell plastic trays on April 1. All cultivars were transplanted to the field on May 12 at the South Farm in LEX and at the Robinson Experiment Station at Quicksand (QSND). Varieties at both locations were planted in a randomized complete-block design with four replications. Plots at LEX consisted of eight plants spaced 18 in. apart in a single row on 6-in.-high raised beds spaced 6 ft apart with black plastic mulch and trickle irrigation. Plots at QSND were similar except that ten plants per plot were used, and beds were spaced 7 ft apart. Plants at both locations were staked and tied using the Florida weave system and were pruned to two main stems.

Eighty-eight lb N, no phosphorus, and 178 lb K2O/acre were applied prior to bed formation at QSND, while 116 lb/acre each of N, P2O5, and K2O were applied at LEX. A total of 26 lb/acre of supplemental N (ammonium nitrate) was fertigated at QSND from June 10 until July 28 in six applications ranging from 2.5 to 5.0 lb N per acre per application. No supplemental N was applied through the drip system at LEX. Both plots were sprayed weekly with protectant fungicides (Bravo at QSND and maneb or Bravo at LEX). In addition, two and three applications of Bravo + Quadris or Quadris alone were made at QSND and LEX, respectively.

A total of eight harvests were made at LEX from July 13 until Aug. 26, while seven harvests were made at QSND from July 14 until Aug. 17. Fruit were graded into the following size classes prior to counting and weighing: Jumbo (>3.5 in. diameter), extra-large (>2.75 in. but <3.5 in.), large (>2.5 in. but <2.75 in.), medium and smalls (<2.5 in.), and culls. Fruits were also sorted according to U.S. No. 1 or U.S. No. 2 grades. In order to approximate the present marketing situation in Kentucky, “marketable yield” included only the “large” and above size classes. Yields of the “medium” size class are reported together with smalls, as they are not considered worth marketing by most grower/shippers in the state. All yields reported in Tables 1 and 2 and shown in Figures 1 and 2 are of U.S. No. 1 fruit unless otherwise indicated. Yields of No. 2 fruits, although marketable in most years, were not included in “marketable yield” and are reported in separate columns in the tables.

In addition to reporting yields in terms of pounds per acre and cartons per acre, variety performance is also expressed as income per acre (Figures 3 and 4). Actual 1998 tomato weekly market prices were multiplied by yields from the different size classes for each variety. Higher prices were used for the earlier harvests in order to favor earlier-maturing varieties. Higher prices were also used for the “extra large and jumbo size” class. Yields of No. 2 fruits were also used in these calculations, but with lower prices than No. 1 fruits. We consider the incomes per acre together with the fruit quality observations in Table 3 to provide the best indication of overall variety performance. Means of all variables were compared using Waller-Duncan’s K-ratio T test (P = 0.05).

Disease assessments

Varieties at QSND were rated for the extent of foliar early blight (Alternaria solani) symptoms on July 20 and August 7. In addition, varieties at LEX were assessed for virus incidence and severity on July 9 and August 6, respectively. Leaf samples collected from all cultivars together with fruit samples from selected cultivars in the LEX trial were sent to Agdia, Inc. of Elkhart, Indiana, for ELISA testing.

Fruit quality ratings

All fruits of each variety from one replication in the QSND trial were graded and laid out for careful examination and quality ratings on Aug. 11. Varieties were rated for smoothness, blossom scar size, extent of cracking, firmness, and internal color (Table 3). The overall appearance rating took most of these factors into account.

Taste tests

All varieties were evaluated informally for taste by a group of four people. From among the 16 varieties, 6 were selected for further evaluation by a much larger group of consumers. Results were still being tabulated at the time of writing and will be presented at a later date.

Results and Discussion

Disease epidemics at both locations affected tomato yields in these trials. A severe epidemic of Tomato Mosaic Virus (ToMV)1 occurred in the LEX trial. The disease was first observed in transplants of a home garden variety that had been grown in the same greenhouse as the trial entries. Six plants of this variety were transplanted to one of the LEX trial guard rows for observation together with some “cluster” type greenhouse tomato varieties from Israel. Virus symptoms were observed in this variety only after staking, pruning, and tying, so that the disease was inadvertently spread throughout the field. The resulting epidemic appeared quite uniform, and leaf samples collected at midseason from all 16 cultivars tested positive for ToMV. We decided to continue with the trial in order to evaluate the impact of ToMV on yield and quality of these varieties. Although ToMV epidemics have rarely occurred in the field in Kentucky, this could change as popular, new (but TMV-susceptible) tobacco cultivars displace cultivars that have TMV resistance. Given the unusual persistence of ToMV/TMV, this disease may also become a problem when greenhouses constructed for tobacco transplant production are used for tomato production during the fall and winter months.

1ToMV is closely related to Tobacco Mosaic Virus (TMV) found in tobacco. Tomato varieties that claim TMV resistance are resistant to ToMV.

Heavy and frequent rains in May and June resulted in standing water in the trial field on at least one occasion at QSND. A moderate natural early blight epidemic occurred in the trial at this location in spite of our best efforts at field drainage and weekly spraying with protectant fungicides. Although early blight always occurs in tomato trials conducted at this location, the extent of the disease in this year’s trial was slightly greater than usual. Since early blight often severely reduces tomato yields in eastern Kentucky, we were especially interested in how cultivars tolerated the disease.

In spite of different diseases occurring at the two locations, 10 out of the 16 cultivars evaluated had the same relative ranking for yields of U.S. No. 1 jumbo and extra large fruit at LEX and QSND; in addition, there were no statistically significant variety x location interactions for this important yield variable in a combined statistical analysis of data from both locations.

‘Mountain Spring’, the most widely grown commercial variety in the state, was lower yielding this year than in previous trials. Its mediocre performance at QSND was probably the result of high susceptibility to early blight associated with this early-maturing variety (Table 1). There was a highly significant negative correlation (r = -0.63, P < 0.01) between total marketable yield and the amount of early blight symptoms observed among varieties. Some of the highest-yielding varieties at QSND (‘Fabulous’ and ‘Sunbeam’) appeared to have some tolerance to early blight. Other cultivars in this highest-yielding group were ‘Emperador’, ‘Enterprise’, ‘Sunleaper’, and ‘Sunbrite’ (Table 1; Figure 1). All of these varieties, with the exception of ‘Sunbrite’, had fruit quality we considered acceptable for commercial markets (Table 3) and will be tested again in 1999. Varieties with early marketable yields at QSND that were greater than or equal to ‘Mountain Spring’ were ‘Sunstart’, ‘Fabulous’, ‘Sunbrite’, ‘Emperador’, ‘Sunleaper’, and ‘SunGem’ (Table 1; Figure 2). ‘Sunstart’ was the earliest-maturing variety in the trial, yielding 75% of its season-long yield in the first three harvests. This variety, together with ‘Mountain Spring’, ‘SunGem’, and RFT 4413, appears to be highly susceptible to early blight (Table1). Although plants of ‘Sunstart’ were smaller and less vigorous than most of the other varieties, it was in the group of highest-income varieties (Figure 3) because of its earliness.

As in QSND, ‘Fabulous’, ‘Emperador’, and ‘Sunleaper’ were in the group of highest-yielding and highest-income varieties in LEX (Table 2; Figure 4). In addition, ‘SunGem’ and ‘Sunpride’ were among the highest yielders at LEX. Superior performance by ‘Fabulous’, ‘Emperador’, and ‘Enterprise’ is to be expected in this trial since each of these cultivars carry the single dominant gene for TMV/ToMV resistance. This is reflected by their low virus incidence and severity ratings in Table 2; however, we observed severe ringspot-like symptoms on most fruits from two plants in one plot of ‘Enterprise’ and occasionally on fruits from plots of ‘Emperador’ and ‘Fabulous’. ELISA tests conducted on ‘Enterprise’ whole fruit samples and on cut-out samples of the ringspot symptoms revealed that these fruits contained very high levels of ToMV. Extracts from these fruits also produced typical TMV/ToMV symptoms when rubbed onto tobacco indicator plants. Similar symptoms have been observed on other TMV/ToMV-resistant tomato varieties (F1 hybrids heterozygous for the resistance gene) exposed to severe TMV/ToMV infections (Jaap Hoogstraten, Asgrow/Seminis, personal communication). ‘Sunleaper’ and ‘Sunpride’ appeared to be somewhat tolerant to TMV in this trial; ‘Sunleaper’ produced the highest income at this location even without the TMV resistance gene (Figure 4). ‘SunGem’ was in the highest-yielding and highest-income group of cultivars in spite of having high virus incidence and severity ratings. There were significant negative correlations between yields of “jumbo and extra large” fruits and both virus incidence (r = -.44, P < .01) and severity (r = -.55, P < .01).

All things considered, new cultivars ‘Sunleaper’, ‘Fabulous’, ‘Emperador’, ‘SunGem’, and ‘Enterprise’ deserve further testing alongside varieties such as ‘Mountain Spring’, ‘Mountain Fresh’, and ‘Sunbeam’, which are already popular in the state. ‘Sunleaper’ is a heat-tolerant variety that has also performed well in late plantings. Another variety we liked was ‘Floralina’, which, together with ‘Mountain Spring’ and ‘Mountain Supreme’, had the highest ratings for overall fruit appearance (Table 3); ‘Floralina’ also scored very high in the taste test (data not shown). ‘Sunstart’ was the earliest-maturing variety tested but did not have very attractive fruits; some growers may want to try it for local markets where they receive a premium for the first tomatoes of the season. It should probably be pruned less than other varieties. The search for the “Kentucky Tomato” will continue next year.

Acknowledgments

The authors would especially like to thank Darrell Slone, Chris Lindon, and Larry Swartz for their hard work and generous assistance in conducting these trials. We also gratefully acknowledge financial support from the cooperating seed companies.

Table 1. Yields and early blight ratings of staked tomatoes at Quicksand, KY, 1998; all data are means of four replications.
Entry (Seed Co.)--#1 Jumbo+XLt--#1 LargeuTot. mkt.v# 2'swMeds.+ SmallsxCullsAv. frt. wt.y oz.Early blight ratingsz
boxes/acre%------------------ lbs/acre x 1000------------------20 July 7 AugAvg.
Fabulous (SW)21378553.4 8.862.23.6 5.23.711.20.7 2.11.4
Emperador (PS)19497948.712.260.93.2 9.54.210.40.92.41.6
Sunbrite (AS)17678044.210.254.46.4 6.12.1 9.91.12.61.9
Sunbeam (AS)16657341.614.355.93.7 10.61.8 9.20.72.21.5
Enterprise (SW)16087140.216.857.05.5 10.57.8 9.31.12.92.0
Sunleaper (RG)14956537.419.657.03.3 12.73.6 9.21.22.61.9
Mtn. Fresh (H)14316735.817.853.62.7 9.61.5 9.10.51.91.2
Florida 47 (AS)14107135.213.949.23.1 8.02.3 9.51.13.02.1
SunGem (AS)13657334.112.446.66.7 11.94.0 9.51.73.12.4
Mtn. Spring (RG)13077132.711.744.36.1 9.95.3 9.41.63.22.4
Floralina (PS)12856432.115.047.13.9 12.13.7 8.51.23.12.2
FTE 30 (SW)12726731.814.546.34.6 9.04.1 8.61.12.21.7
RFT 4413 (RG)12397031.012.543.53.8 8.52.4 9.31.72.92.3
Sunstart (AS)12306830.713.444.17.4 10.27.4 8.91.43.52.4
Sunpride (AS)10746026.817.344.12.4 11.92.7 8.50.92.61.7
Mtn. Supreme (AS)10215825.518.644.11.9 17.72.9 7.90.00.60.3
Waller-Duncan LSD (P = 0.05) 5381013.5 4.516.91.96 4.72.2 0.7----0.9
tYields of USDA No. 1 fruit of jumbo (>3.5 in. diameter) plus extra large (>2.75 in but 3.5 in) size classes; boxes/acre = number of 25-lb cartons per acre; "%" = percentage of the total of these two size classes out of the total marketable yield.
uYields of USDA No. 1 fruit of the large (>2.5 in but 2.75 in) size class.
vTotal marketable yield = yield of No. 1 fruit of jumbo + extra large + large size classes; mediums not included.
wYield of USDA No. 2 fruit from all size classes.
xYield of medium + small size classes (2.5 in, unmarketable in most years in KY).
yAverage fruit weight; includes size classes jumbo, extra large, and large only.
zAssessed for foliar symptoms of Alternaria solani on 20 July and 7 Aug using a 0-5 rating scale where 0 = no symptoms, 1 = slight symptoms, 3 = moderate symptoms, 5 = severe symptoms and some defoliation; "Avg." is the average rating of the two assessment dates.

Table 2. Yields and Tomato Mosaic Virus (ToMV) ratings of staked tomatoes at Lexington, Kentucky, 1998; all data are means of four replications.
Entry (Seed Co.)--Jumbo+XLt-- #1 LargeuTot. mkt v# 2'swMeds.+ SmallsxCullsAvg. frt. wt.yVirus z
boxes/acre%------------------lbs/acre x 1000------------------oz. Incidence %Severity rating
Fabulous (SW)18039845.00.745.87.71.512.7 9.8 12 0
Emperador (PS)17919544.81.846.64.80.611.410.5 250.2
Sunleaper (RG)17459143.63.947.54.21.1 6.2 8.7 871.7
SunGem (AS)15749639.31.540.83.00.4 4.7 9.51003.0
Enterprise (SW)15619539.01.940.97.50.518.4 9.4 6 0
Sunpride (AS)15098837.75.242.93.35.0 6.8 7.9 941.7
Sunbeam (AS)14149035.33.739.06.40.7 7.6 8.5 912.0
Mtn. Fresh (H)13749134.33.537.85.30.6 8.4 9.11002.0
Florida 47 (AS)13688834.25.239.47.10.810.2 9.5 972.2
Mtn. Spring (RG)13539533.81.735.54.40.4 8.1 9.11003.0
Floralina (PS)13489333.72.536.23.90.8 7.0 8.5 972.5
Sunbrite (AS)13369733.41.034.44.90.4 8.8 9.9 752.5
RFT 4413 (RG)13359633.41.334.72.90.1 9.7 9.01001.5
Sunstart (AS)10638826.63.930.53.90.8 9.8 8.31003.0
FTE 30 (SW)10489526.21.427.65.50.511.7 8.9 942.7
Mtn. Supreme (AS) 7267218.16.825.00.93.7 2.8 6.61002.5
Waller-Duncan LSD (P = 0.05) 306 6 7.63.3 8.42.6ns 3.9 0.8 240.2
tYields of USDA No. 1 fruit of jumbo (>3.5 in. diameter) plus extra large (>2.75 in but 3.5 in) size classes; boxes/acre = number of 25-lb cartons per acre; "%" = percentage of the total of these two size classes out of the total marketable yield.
uYields of USDA No. 1 fruit of the large (>2.5 in but 2.75 in) size class.
vTotal marketable yield = yield of No. 1 fruit of jumbo + extra large + large size classes; mediums not included.
wYield of USDA No. 2 fruit from all size classes.
xYield of medium + small size classes (2.5 in, unmarketable in most years in KY).
yAverage fruit weight; includes size classes jumbo, extra large, and large only.
zFoliar symptoms of ToMV; incidence (%) = percentage of plants exhibiting symptoms on 9 July; severity of visual symptoms on 6 Aug where 0 = no ToMV symptoms visible, 1 = late symptom development and/or mild mosaic visible, 2 = intermediate symptom development, 3 = strong mosaic and leaf deformation at all levels of the plant.

Table 3. Fruit quality characteristics; observations from all fruits from one replication at Quicksand, 11 August 1998. Cultivars ranked in order of yield of jumbo and extra large fruits.
Cultivar (Seed Co.)ShapetBlossom scaruSmoothnessvCrackingwAppearancexFirmnessyInternal colorzComments
Fabulous (SW)dos32742Large fruits are angular
Emperador (PS)dos2.536.532Some radial cracking; air spaces in locules in few fruits.
Sunbrite (AS)dos34532Large radial cracks; air spaces in locules frequent
Sunbeam (AS)do-gs2363.52.5Some radial cracking.
Enterprise (SW)gs-m22645Nice internal color.
Sunleaper (RG)dos22744Few concentric cracks & rain checking
Mtn. Fresh (H)gs22744No complaints!
Florida 47 (AS)gs22744Some rain checking.
SunGem (AS)dos22743Some rain checking.
Mtn. Spring (RG)dos21843Nice; light internal color.
Floralina (PS)do-gs-m21843.5Nice fruits.
FTE 30 (SW)dos2.52.563.53.5Some cracking.
RFT 4413 (RG)do-gs2274.53Some fruits. with few locules
Sunstart (AS)dos22.5532.5Severe rain checking, rough skin.
Sunpride (AS)dos23545Serious radial cracking.
Mtn. Supreme (AS)dos21844
tFruit shape: "do" = deep oblate (diameter somewhat greater than height), "g" = globe (spherical).
uBlossom scar size: "s" = small (< 1/8 in. diameter), "m" = medium (1/8 to 1/4 in).
vSmoothness of fruit rating: 1 = smooth (best), 5 = ribbed on top (worst).
wFruit cracking: 1 = none, 5 = severe.
xOverall fruit appearance rating: 1 = worst, 9 = best.
yFruit firmness by feel: 1 = soft, 3 = medium firm, 5 = very firm.
zInternal fruit color: 1 = whitish (worst), 5 = uniformly deep red (best).

Figure 1. Jumbo+XL and Total Marketable* Yields.

Figure 2. Early* Jumbo+XL and Total Marketable**.

Figure 3. Income Per Acre*.

Figure 4. Income Per Acre*.

Analysis of Organic Fertilizers for Use in Vegetable Transplant Production

Robert Hadad and Robert G. Anderson, Department of Horticulture & Landscape Architecture

Introduction

Many farmers have an interest in using organic fertilizers for vegetable transplant production. There are no general recommendations for using organic fertilizers, because historically, organic fertilizers are generally insoluble in water, and nutrients are slowly available. Because of their insolubility, organic fertilizers have not been applied through the use of injectors in a typical greenhouse transplant production system. This research was conducted to observe how vegetable transplants would grow on a modified “float” bed using organic fertilizers.

Materials and Methods

The “raft” system

The transplant growing technique used, called the “raft” system, is an adaptation of the controlled water table subirrigation system developed by Dr. Jack Buxton. The raft system utilizes a piece of polystyrene floating on the water of the “float” bed. A capillary mat (water absorbent fabric) is draped across the polystyrene and into the water on each side. Water is wicked up to the surface by capillarity to keep plants uniformly moist during production. The capillary mat is covered with a landscape fabric, Weed-X, that prevents root penetration into the mat yet allows water to pass through to the plants. This system allows the use of slowly soluble organic fertilizers for transplant production.

Five organic fertilizers were selected based on their advertised solubility in water and their use by growers. These products were purchased from Peaceful Valley Farm Supply, P.O. Box 2209, Grass Valley CA 95945, (916) 272-4769, and are listed below.

Inorganic fertilizers are generally simple to use, because it is easy to determine the fertilizer concentration with the use of a conductivity meter. Standard tables allow plants to be fertilized with a desired amount of nitrate nitrogen by its relation to the electrical conductivity of the fertilizer solution—so it is easy to mix a fertilizer solution and determine the nitrate nitrogen concentration before applying it to the plants.

Organic fertilizers have been difficult to apply at a specific rate because the amount of nutrients per unit of fertilizer solution were not known. In order to determine amounts of the selected fertilizers that should be used for transplants, mixtures of the fertilizers were analyzed. The fertilizers were mixed at ½, 1, 2½, and 5 times the manufacturer’s recommended rates in one gallon of water. The mixtures were allowed to stabilize for 2 hours; then a subsample of 1 pint of fertilizer water was removed. This sample was refrigerated to stop metabolic activity and brought to the Soil Testing Lab for water solution analysis. The analyses are presented in Tables 2 through 6.

Results and Discussion

The organic fertilizers were successful for plant production. Plants grown on the “raft” subirrigation system appeared normal. Vegetable transplants would typically be grown with 50 to 70 ppm nitrate nitrogen of an inorganic fertilizer in a subirrigation system. Based on the standardized water analyses reported here, Algamin would be used at 4 to 5 Tbs per gallon, bat guano at 1.5 to 2 Tbs per gallon, fish emulsion at 4 to 5 Tbs per gallon, Maxicrop at 3/4 to 1 tsp per gallon, and Mermaid’s Fish Powder at 2 to 4 Tbs per gallon to meet this standard.

Based on the standards for inorganic fertilizers, the analyses demonstrated that there would be advantages and disadvantages to the use of these organic fertilizers.

The knowledge of the efficacy of inorganic fertilizers is based on years of testing and experience. The efficacy of organic fertilizers for plant growth in greenhouse systems will require a significant amount of time because there is little knowledge of how the organic nutrients become available to plant roots and how specific mixtures of organic fertilizers can be adapted for good plant nutrition.

Table 1. Organic fertilizers with reputed solubility in water for applications in plant production systems.
Fertilizer NameGuaranteed AnalysisOriginManufacturerRecommended Rate
Algamin (liquid)0.2-0.0-0.4
0.2% water-soluble organic nitrogen
Extract of processed seaweed from Norway, Ascophyllum nodulosum.Peaceful Valley Farm Supply, P.O. Box 2209 Grass Valley CA 959452 Tbs/gal
Bat Guano 10-3-1
5.0% water-soluble organic nitrogen
5.0% water-insoluble organic nitrogen
Dried bat manure from dry caves in South America. Down to Earth Distributors, Inc, Eugene, OR 974014 Tbs/gal
GreenAll Fish Emulsion (liquid)5-2-2
0.4% ammoniacal nitrogen
3.6% water-soluble organic nitrogen
1.0% water-insoluble organic nitrogen
Liquid concentration of fish scraps.E.B. Stone & Sons, Inc. Suisun CA 945852 Tbs/gal
Ohrstrom's Garden Maxicrop (powder)1.0-0.0-4.0
1.0% water-soluble nitrogen
Extract of processed seaweed from Norway, Ascophyllum nodulosum.Maxicrop USA, Inc. P.O. Box 964 Arlington Heights IL 600061 tsp/gal
Mermaid's Fish Powder12-0.25-12.0% ammoniacal nitrogen
6.0% other water-soluble nitrogen
4.0% water-insoluble nitrogen
Dried fish protein digest.Integrated Fertility Management, Inc. 333 Ohme Gardens Rd. Wenatchee WA 988012 Tbs/gal

Table 2. Analysis of nutrients from water samples mixed with ½, 1, 2½, and 5 times recommended rate of Algamin organic fertilizer in one gallon of water.
1 Tbs per gallon (½ rate)2 Tbs per gallon (recommended rate)5 Tbs per gallon (2½ rate)10 Tbs per gallon (5 rate)
pH6.786.686.285.62
Conductivity (mmho/cm)0.450.631.081.95
Alkalinity (ppm)33474352
Nitrate-Nitrogen (ppm) 172580111
Phosphorus (ppm)1124
Potassium (ppm)162756133
Calcium (ppm)25313862
Magnesium (ppm)294276143
Zinc (ppm)0.10.10.10.3
Copper (ppm)0000
Iron (ppm)00.10.30.8

Table 3. Analysis of nutrients from water samples mixed with ½, 1, 2½, and 5 times recommended rate of bat guano organic fertilizer in one gallon of water.
2 Tbs per gallon (½ rate)4 Tbs per gallon (recommended rate)10 Tbs per gallon (2½ rate)20 Tbs per gallon (5 rate)
pH4.143.513.162.96
Conductivity (mmho/cm)0.520.91.83.5
Alkalinity (ppm)0000
Nitrate-Nitrogen (ppm)64128247520
Phosphorus (ppm)195085210
Potassium (ppm)2562127305
Calcium (ppm)33343747
Magnesium (ppm)9101422
Zinc (ppm)0.30.512.1
Copper (ppm)0000
Iron (ppm)00.10.40.9

Table 4. Analysis of nutrients from water samples mixed with ½, 1, 2½, and 5 times recommended rate of fish emulsion organic fertilizer in one gallon of water.
1 Tbs per gallon (½ rate)2 Tbs per gallon (recommended rate)5 Tbs per gallon (2½ rate)10 Tbs per gallon (5 rate)
pH7.337.347.467.37
Conductivity (mmho/cm)0.540.681.11.8
Alkalinity (ppm)7680146236
Nitrate-Nitrogen (ppm)123268110
Phosphorus (ppm)68122191462
Potassium (ppm)66147240593
Calcium (ppm)34333539
Magnesium (ppm)13152025
Zinc (ppm)0000.2
Copper (ppm)0000.1
Iron (ppm)0000.1

Table 5. Analysis of nutrients from water samples mixed with ½, 1, 2½, and 5 times recommended rate of Maxicrop organic fertilizer in one gallon of water.
½ tsp per gallon (½ rate)1 tsp per gallon (recommended rate)2½ tsp per gallon (2½ rate)5 tsp per gallon (5 rate)
pH7.637.337.216.89
Conductivity (mmho/cm)0.560.751.62.1
Alkalinity (ppm)123150265350
Nitrate-Nitrogen (ppm)3269176370
Phosphorus (ppm)0011
Potassium (ppm)113150500714
Calcium (ppm)28253335
Magnesium (ppm)1291720
Zinc (ppm)0.200.20.3
Copper (ppm)0000
Iron (ppm)000.10.7

Table 6. Analysis of nutrients from water samples mixed with ½, 1, 2½, and 5 times recommended rate of Mermaid's Fish Powder organic fertilizer in one gallon of water.
1 Tbs per gallon (½ rate)2 Tbs per gallon (recommended rate)5 Tbs per gallon (2½ rate)10 Tbs per gallon (5 rate)
pH6.826.576.526.41
Conductivity (mmho/cm)0.350.491.01.1
Alkalinity (ppm)95165463529
Nitrate-Nitrogen (ppm)144091170
Phosphorus (ppm)6112038
Potassium (ppm)15306697
Calcium (ppm)27262120
Magnesium (ppm)10101111
Zinc (ppm)0000
Copper (ppm)0000
Iron (ppm)0000


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