University of Kentucky College of Agriculture
ENTFACT-421

Controls for Greenhouse Ornamental Insect Pests

by Ric Bessin, Extension Entomologist
University of Kentucky College of Agriculture

 

The warm humid conditions and abundant food in the greenhouse are ideal for pest build up. Problems can be chronic unless recognized and corrected. While insecticides are important tools, successful control of greenhouse ornamental pests relies primarily on cultural factors. Proper cultural practices can minimize the chance for initiation and build up of infestations. Early detection and diagnosis are key to greenhouse pest management, as well as, the proper choice and application of pesticides when pest outbreaks occur.

 

Cultural Controls

Pests may enter the greenhouse in the summer when the ventilators are open. Others may be brought into the greenhouse on new plant material or in soil. Many are able to survive short periods of time between harvest or plant removal and production of the next crop. Cultural controls are the primary defense against infestation.

 

Proper cultural practices which will help prevent pest infestations include:

  • Maintain a clean, closely mowed area around the greenhouse to reduce pests that develop in rank growth.
  • Remove all plants and any plant debris, clean the greenhouse thoroughly after each production cycle.
  • Keep doors, screens and ventilators in good repair.
  • Use clean or sterile soils or ground media, tools, flats and other equipment.
  • At the conclusion of the season remove all plants and any plant debris, clean greenhouse thoroughly and fumigate.
  • Inspect new plants thoroughly to prevent introduction insect or disease infested material into the greenhouse.
  • Watch for leaks or pooled water that can lead to fungus gnat infestations.
  • If possible allow the greenhouse to freeze in winter to eliminate tender insects like whiteflies.
  • Avoid wearing yellow clothing which is attractive to many insect pests which can be carried into the greenhouse from outside.
  • Eliminate infestations by discarding or removing heavily infested material.

 

Pest Monitoring

Early detection and diagnosis of pest infestations will allow you to make pest control decisions before the problem gets out of hand. It is good practice, therefore, to make weekly inspections of plants in all sections of the greenhouse.

 

Insect monitoring devices are also available. Yellow sticky cards (PT Insect Monitoring & Trapping System, Whitmire) are highly attractive to winged aphids, leafminer adults, whiteflies, leafhoppers, thrips (blue cards can also be used with thrips), various flies and other insects. These can be used to alert you to the presence of a pest and identify hot spots in the greenhouse. One to three cards per 1000 sq. ft. in the greenhouse is recommended and should be changed weekly. If you cannot identify a trapped insect, contact your county extension agent for assistance. Mass trapping products such as sticky tapes are also available for thrips, whitefly, leafminer and fungus gnat detection and management.

 

Insecticide Resistance Management

Many of the most serious greenhouse pests tend to be small insects (or mites) with short life cycles and high birth rates. This includes spider mites, aphids, whiteflies and thrips. Development of insecticide resistance is a potential problem with these pests. Susceptible individuals in a pest population are wiped out when chemicals with the same mode of action are applied repeatedly. The proportion of resistant individuals in a population increases and they become more difficult to control. Unfortunately, a grower may increase usage of the pesticide in response to this until it no longer provides control.

 

As a greenhouse manager, there are several tactics to prevent, delay or reduce insecticide resistance. Countermeasures include reducing the frequency or extent of insecticide treatments, reducing the use of insecticides with long residual action, avoiding treatments which act upon both larva and adults, and including nonchemical methods of biological and cultural control into an integrated pest mangement program.

 

Phytotoxicity to Pesticides

Not all varieties of each plant species has been tested with these registered pesticides. Plant response to these pesticides may vary in your greenhouse. Specific environmental factors in your greenhouse greatly affect phytotoxicity. All pesticides should be tested on a small group of plants to be treated at the recommended rate under anticipated growing conditions for phytotoxic symptoms. Signs of phytotoxicity may take 1 to 14 days to develop.

 


 

Alphabetical listing of common insecticides (trade names), the pests they control, and a listing of safe and sensitive plants, comments also.

Using the format below:

 

Common Name (Trade Names)
Pests controlled
Safe plants
Sensitive plants
Comments

 

A

Common Name (Trade Names): Abermectin (Avid 0.15EC)
Pests controlled: Spider mites (all motile forms), leafminers
Safe plants: Various ornamentals
Sensitive plants: Do not use on ferms or conifers.
Comments: Insecticide/miticide: May require 3 to 4 days to achieve maximum
effectiveness.

 

Common Name:Acephate (Orthene Turf, Tree and
Ornamental Spray, PT 1300 TR, Orthene, PT 1300 DS Orthene)
Pests controlled:Aphids, cabbage loopers, lacebugs, leafminers, leafrollers, mealybugs, plant bugs, scale crawlers, sweet potato whitefly, thrips, whiteflies
Safe plants:Roses, orchids, anthuriums, cacti, poinsettia, carnations, chrysanthemums, impatients, marigolds, petunias, geraniums, snapdragons, fuchia, lantana, New Guinea impatiens, ivy, geraniums, boston fern, dracaena, ficus, schefflera, philodendron, lillies, african violets, hibiscus, begonia, azalea, viburnum, yew
Sensitive plants: Do not apply to american elm, flowering crabapple, sugar maple, and cottonwood.
Comments: An organophosphate insecticide. Do not apply to roses or chrysanthemums with open flowers.

 

B

Common name (Trade name): Bacillus thuringiensis var azawai(XenTari)
Pests Controlled: Armyworm, loopers, Heliothis
Safe plants: Flowers, bedding plants, herbs, and ornamentals.
Comments: A biological insecticide that attacks the gut and must be injested. Does not kill adults. Toxic to the predatory mite Metaseiulus occidentalis and green lacewing.

 

Common name (Trade name): Bacillus thuringiensis kurstaki(Dipel 2X, Javelin WG, Steward)
Pests Controlled: Armyworm, loopers, Heliothis
Safe Plants: Flowers, bedding plants, herbs, and ornamentals
Comments: A biological insecticide that attacks the gut and must be injested. Does not kill adults.

 

Common name (Trade name): Bacillus thuringiensis Serotype H-14 (Gnatrol)
Pest controlled: Fungus gnat larvae
Safe Plants: Ornamentals
Comments: A biological insecticide that attacks the gut and must be injested. Apply as a soil drench. Does not kill adults.

 

Common name (Trade names): Bendiocarb (Dicarb, Turcam)
Pests Controlled: Aphids, thrips, mealybugs, greenhouse whitefly, black vine weevil, scales, collembola
Safe Plants: Ornamental plants including: african vioiet, ageratum, aglaonema, aralia, asarina, asparagus sprengeri, begonia, calathea, calendula, camellia, carnation, celosia, chrysanthemum, coleus, cottoneaster, Croton,daffodil, dahlia, dianthus, dieffenbachia, dracaena, epipremnum, episcia, fatsia, ferns, ficus, fountain grass, fuchsia, gazania, geranium, gladiolus, gloxinia,hydrangea, hypoestes, impatiens, iris, ivy, ixora, leucothoe, lily of the vailey, maranta, marigold, mondo grass, nandina, nasturtium, nicotiana, pansy, peperomia, petunia, philodendron, photinia, pieris, poinsettia, portulaca, pothos, primrose, rose, sago palm, salvia, sansevieria,schemera, shasta daisy, sinningia, snapdragon, spathiphyllum, spirea, sycamore, verbena, viburnum, vinca, wandering jew, and zinnia.
Comments: A carbamate insecticide.

 

Common Name (Trade Names) ::Bifenthrin (PT 1800 Attain,
Talstar T&O 10 WP, Talstar T&O Flowable)
Pests Controlled: Aphids, armyworms, brown soft scale, caterpillars, fungus gnats, cutworms, loopers, mealybugs, plant bugs, scale, whiteflies, spider mites, thrips, leafminers
Safe Plants:Ornamental and flowering plants
Comments: A synthetic pyrethroid insecticide. Apply during early evening when foliage is dry and temperature is between 60 - 80 F. Use an alternate class of chemistry in a treatment program to delay or prevent resistance.

 

C

Common Name (Trade Names)::Chlorpyrifos (Dursban 50 WP, PT 1325 ME Duraguard, Pageant DF)
Pests Controlled: Ants, aphids, beetles, caterpillars, centipedes, crickets, leafhoppers, mealybugs, plant bugs, scale, sowbugs, thrips (exposed), whiteflies
Safe Plants:Ornamental and flowering plants
Sensitive plants:Do not use on croton, schefflera, zebra plant, copperleaf, black olive, papayas, cissus, ficus, weeping fig, Cuban laurel, yellow hibiscus, red/Chinese hibiscus, impatients, Boston fern, petunia, and some roses.
Comments: An organophosphate insecticide. Direct spray to some open blooms may cause petal drop. Do not use additional wetting agents, spreaders or
stickers.

 

Common Name (Trade Names):Cyfluthrin (Tempo 2, Tempo 20 WP, Decathalon)
Pests Controlled: Armyworms, cutworms, flies, crickets, fungus gnats, sowbugs, ants, aphids, flea beetles, leafhoppers, plants bugs, mealybugs, thrips, scales, whiteflies
Safe plants: Ornamentals
Comments: A synthetic pyrethroid insecticide.

 

Common Name (Trade Names):Cyromazine (Citation 75 WP)
Pests Controlled: Leafminers
Safe plants: Container grown chrysanthemums
Comments: An insect growth regulator. It has some systemic effects, but should be applied as a high volume spray.

 

D

Common Name (Trade Names): Diazinon (Knox-Out 2FM PT 265, Knox-Out PT 1500R)
Pests Controlled: Ants, aphids, caterpillars, crickets, fungus gnat larvae, leafminers, loopers, mealybugs, millipedes, mites, scales, thrips
Safe plants: Various ornamentals
Do not use on bella palm, dracaena, hoya, maidenhair fern, neath, poinsettia, and prayer plant.
Comments: An organophosphate insecticide.

 

Common Name (Trade Names):Dibrom (Naled 8 E)
Pests Controlled: Spider mites, adult whiteflies, aphids, leafrollers, mealybugs
Safe plants: Roses and other ornamental plants. Often used as a vapor treatment when applied on heat pipes.
Comments: An organophosphate insecticide.

 

Common Name (Trade Names): Dicofol (Kelthane 35, Kelthane 50)
Pests Controlled: Mites
Safe plants: Ornamental and flowering plants
Comments: A miticide.

 

Common Name (Trade Names):Dienochlor (Pentac Aquaflow, Pentac WP)
Pests Controlled: Two-spotted spider mite, European red mite, broad mites
Safe plants: Most ornamental plants including: roses, chrysanthemum, carnation, gardenia, poinsettia, snapdragon, zinnia, delphinium, palms, maranta, zebra plant, schefflera, dieffenbachia, aphelandra
Comments: A miticide.

 

E

Common Name (Trade Names):Endosulfan (Thiodan T&O 3EC, Thiodan T&O 50WP)
Pests Controlled: Aphids, whiteflies, cyclamen mite
Safe plants: Ornamentals
Sensitive plants:Do not use on 'Bnafon Deluxe', 'Fred Shoesmith' or 'White Knight' chrysanthemums.
Comments: A chlorinated hydrocarbon insecticide. On chrysanthemums, apply before plants flower for best results.

 

F

Common Name (Trade Names):Fenoxycarb (PT 2100 TR Preclude)
Pests Controlled: Whiteflies, thrips, scale, aphids
Safe plants: Bedding plants, cut flowers, potted plants, foliage and flowering plants, and ornamentals
Comments: An insect growth regulator. Apply during early evening when foliage is dry and temperature is between 60 - 80 F.

 

Common Name (Trade Names):Fenpropathrin (Tame 2.4 EC)
Pests Controlled: Aphids, beet armyworm, mealybugs, greenhouse whitefly, lace bugs, leafhoppers, two-spotted spider mite, sweet potato whitefly
Safe plants: Ornamental plants including: Anthurium, bedding plants, chamomile, chrysanthemum, crossondra, columbine, foliage plants, geranium, gladiolus, impatients, liriope, lilly, mrigold, poisettia, snapdragon, azalea, croton, camellia, cotoneaster, gardenia, hibiscus, rose, viburnum.

Comments: A synthetic pyrethroid insecticide.

 

Common Name (Trade Names):Fluvalinate (Mavrik Aquaflow)
Pests Controlled: Aphids, thrips, mites, whiteflies, flea beetles, leafhoppers, plant bugs, leaf-feeding caterpillars
Safe plants: Ornamentals
Comments: A synthetic pyrethroid insecticide. May work slowly on some species. Allow 3 to 4 days to evaluate performance. Piperonyl butotoxide will aid in the control of some pest species such as whiteflies, aphids, thrips, and mealybugs.

 

H

Common name (Trade name): Horticultural oil (SunSpray Ultra Fine Spray oil)
Pests controlled: Aphids, fungus gnat, leafminers, mealybugs, scales, spider mites, whiteflies
Safe plants: Azaleas, begonias, camelias, chrysanthemums, Easter lilles, ferns, gardenias, hibiscus, jade plant, New Guinea impatients, palms, philodendron, portulaca, reigor begonias, zinnias, poinsettia, dieffenbachia
Sensitive plants: Do not use on coconut palms or maidenhair ferns. Blooms of chrysanthemums and geranium may show injury at higher rates. Do not use on poinsettia
bracts. Some bleaching and spotting has been observed on open blooms.
Comments: Most effective on whitefly during immature stages. Kills insect by suffocation. Complete coverage is necessary. Is incompatible with pesticides containing sulfur.

 

I

Common Name (Trade Names):Imadacloprid (Marathon 1G)
Pests Controlled: Aphids, mealybugs, thrips, whiteflies
Safe Plants:Ornamental flowering, foliage, and bedding plants
Comments: A systemic insecticide. Do not apply to soils which are water-logged, or saturated which will not allow penetration of water into the root zone of the plants. Do not over-irrigate or allow excessive runoff to occur following application.

 

Common Name (Trade Names):Insecticidal soap (M-pede, Safer, Ringer Attack)
Pests Controlled: Aphids, lace bugs, leafhoppers, plant bugs, mealybugs, mites, scales, thrips, whiteflies
Safe plants: Flowers and bedding plants
Sensitive plants:Do not use on azaleas, begonias, bleeding heart, camellias, crown of thorns, fuchias, gardenia, impatients, jade plants, lantana, lillies, palms, or sweet peas. Do not use on transplants or root cuttings. Test on euphorbias, chrysanthemums, dracaena, dieffenbachia, ivies, palms and succulents before using. Do not apply to open blooms.
Comments: Avoid application when temperatures exceed 90 F.

 

K

Common Name (Trade Names):Kinoprene (Enstar 5E, Enstar II)
Pests Controlled: Immature whiteflies, aphids, soft and armored scales, mealybugs, fungus gnats
Safe plants: Ornamental plants including: aluminum plant, azalea, Boston fern, bromeliad, chrysanthemum, devil's ivy, dianthus, dracaena compacta, emerald gem nephthylis, English ivy, epipremnum aureum, exotica perfection dumbcane, false aralia, fluffy ruffles fern, fuchsia, geranium, gerbera, gloxinia, heartleaf philodendron, hydrangea,kalanchoe, lantana, lily, marigold, pelargonium, petunia, purple passion plant, red-veined prayer plant, Sanders dracaena, snapdragon, table fern, variegated oval leaf peperomia, wax plant, weeping fig, areca palm, aucubifolum [cotton], coleus varieties, coral ardisia, grape ivy, neanthebelle palm, and sprengeri fern, zebra plant
Sensitive plants:Do not use on some poinsettia and rose varieties.
Comments: An insect growth regulator. May cause some damage to blooms under certain conditions, apply in the prebloom stage.

 

N

Common Name: (Trade Names):Neem (Azatin, Margosan-O)
Pests Controlled: Whiteflies, thrips, mealybugs, leafminers, loopers, caterpillars, beet armyworm
Safe plants: Bedding plants, potted plants, foliage plants, ornamentals, trees and
shrubs
Comments: An insect growth regulator. Do not add surfactants. Do not apply when temperatures will exceed 90 F.

 

Common Name (Trade Names):Nicotine (Nicotine Smoke Generator)
Pests Controlled: Aphids, thrips, chysanthemum and rose midge, whiteflies
Safe plants: Greenhouse ornamentals
Sensitive plants:Do not use on African violets. Do not fumigate tender plants.
Comments: A botanical insecticide.

 

P

Common Name (Trade Names):Permethrin (Pounce T&O 25 WP, Pounce T&O 3.2 EC)
Pests Controlled: Cabbage looper, beet armyworm, omnivorous leafroller
Safe plants: Greenhouse roses
Sensitive plants:Some rose varieties are sensitive to permethrin. Treat a small number of plants to determine plant safety prior to commercial use.
Comments: A synthetic pyrethroid insecticide.

 

Common Name (Trade Names):Pyrethrin + PBO (PT 1100 Pyrethrum, X-clude PT 1600 A, Pyrenone)
Pests Controlled: Ants, aphids, beetles, caterpillars, fungus gnats, leafhoppers, mealybugs, moths, plant bugs, scale, spider mites, whiteflies
Ornamental and flowering plants
Sensitive plants:Do not use on cyclamen or nasturtium
Comments: A botanical insecticide and a synergist.

 

R

Common Name (Trade Names): Resmethrin (PT 1200 TR, PT 1200 DS)
Pests Controlled: Ants, aphids, armyworms, beetles, caterpillars, centipedes,
fungus gnats, lacebugs, leafhoppers, mealybugs, milipedes, plant bugs, scale,
sowbugs, thrips, whiteflies
Safe plants: Bedding plants, cut flowers, foliage and flowering plants and ornamentals
Comments: A synthetic pyrethroid insecticide.

 

S

Common Name (Trade Names): Steinernema carpocapsa (Exhibit)
Pests Controlled: Root weevils and grubs, fungus gnat larvae, shore fly larvae
Safe plants: Ornamentals
Comments: Biological larvicide containing parasitic nematodes. Incompatible with some other pesticides. See label for guidelines.

 

Common Name (Trade Names): Sulfotep (Plantfume 103)
Pests controlled: Spider mites, thrips, soft brown scale, mealybugs, whitefly
Safe plants: Various ornmentals
Comments: An organophosphate insecticide.

 

Revised: 1/04

 

CAUTION! Pesticide recommendations in this publication are registered for use in Kentucky, USA ONLY! The use of some products may not be legal in your state or country. Please check with your local county agent or regulatory official before using any pesticide mentioned in this publication.

 

Of course, ALWAYS READ AND FOLLOW LABEL DIRECTIONS FOR SAFE USE OF ANY PESTICIDE!

 

Images: University of Kentucky Entomology.