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Greenhouse IPM: Sustainable Aphid Control

Lane Greer
NCAT Agriculture Specialist
© NCAT 2000

Photo Courtesy of Hecules Inc., Handbook of the Insect World 60p. Wilmington, DE


The following document focuses on least-toxic methods for dealing with aphids in greenhouses. For general information on greenhouse IPM, see ATTRA's publication Integrated Pest Management for Greenhouse Crops, which covers topics such as screening to eliminate pests, weed management, and disease control.

Table of Contents


There are approximately 4,000 aphid species in the world. Life cycles and preferred hosts vary with each type of aphid. Common aphid pests of greenhouse crops include the green peach aphid (Myzus persicae), the melon/cotton aphid (Aphis gossypii), the chrysanthemum aphid (Macrosiphoniella sanborni), the rose aphid (Macrosiphum rosae), the potato aphid (Macrosiphum euphorbiae) and the foxglove aphid (Aulacorthum solani).(1)

The green peach aphid is probably the most notorious aphid pest of greenhouse crops because of its wide host range, worldwide distribution, number of viral diseases it vectors, and difficulty of control.(2)

Aphid management relies on understanding that the females of many aphid species do not have to mate in order to reproduce, and they typically produce live young, rather than eggs. These characteristics contribute to the tendency of aphid populations to "explode."

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Crop Scouting and Trapping

Plants should be visually inspected for signs of an aphid infestation. Look especially carefully at plants prone to aphid problems, and at plant parts like the undersides of leaves, stems, and new growth. Choose plants randomly throughout the greenhouse and inspect undersides of leaves, buds or tip growth and watch for honeydew and cast skins. Since aphids are difficult to see on plants with fine foliage, hold such plants over a white piece of paper and gently tap to dislodge any aphids. Avoid moving infested plants to new areas where susceptible plants are growing. Locations where aphids are found should be flagged, so that population development and control efforts can be evaluated.

Different aphid species tend to populate different parts of their host plants. Green peach aphids tend to cluster on the succulent young growth, whereas melon aphids are usually evenly distributed along the plant stems. Melon aphid populations also have fewer winged adults than do green peach aphids. Knowing which species is infesting the crop is very important in successful detection and monitoring of aphid populations. The Cooperative Extension Service is a good resource for identification of specific aphid pests.

Yellow sticky cards placed horizontally at the top of the pot or container (if you are growing containerized plants) can be used for monitoring winged aphids. However, since winged aphids caught during the summer months may have blown in from the outdoors, sticky cards are not as reliable as visual inspections. Sticky cards are more useful in the winter months when aphids caught on the cards are not likely to have come in from the outside. It is better to rely primarily on visual inspections for aphid detection, and use sticky cards as a backup method.

Signs of an aphid infestation include honeydew or sooty mold on leaves, yellow spots on upper leaf surfaces, cast skins on leaves, curling of leaves, and distortion of new growth.

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Biological Control

There are several biological control options for greenhouse aphid pests. Some common biological control agents (BCAs) include green lacewings (Chrysoperla carnea, C. rufilabris, Chrysopa spp.), aphid midges (Aphidoletes aphidimyza), parasitic wasps (Aphidius colemani and Aphidius matricariae) and lady beetles (Hippodamia convergens). See Appendix 1: Beneficial Organisms for more BCAs and suppliers.

A 1998 study showed that green lacewing larvae did not disperse as well as the parasitic wasp Aphidius colemani.(3) To achieve equal aphid suppression, more of the slower-moving species need to be introduced and from more points (lacewings have to be released on each bench because they cannot move to adjacent benches, for instance). A study performed at Colorado State University compared the effectiveness of parasitic wasps, aphid midges, lady beetle larvae, and green lacewing larvae.(4) The researchers found that lacewings performed better in hot temperatures, while aphid midges and lady beetles were better in cooler temperatures. At all temperatures, Aphidoletes was the best of the four at controlling aphids.

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Biorational Pesticides

Strains of the fungus Beauveria bassiana provide good control of aphids, including green peach aphids. The fungus works by attaching to the outside of the pest, then penetrating into the body and killing it. The fungus is available commercially for greenhouse ornamentals as Naturalis-O™ and for vegetables as BotaniGard™. (See below for suppliers.)

Another fungus, Verticillium lecanii, can also provide good biological control of aphids. Formulations of this fungus are currently being sold in some European countries under the names of Vertalec™ and Mycotal™, but neither of these products is yet registered for use in the United States.

Verticillium lecanii often occurs naturally in greenhouses, so it may be possible to encourage its growth and distribution in the greenhouse without the benefit of a commercially available product. V. lecanii spores require at least 93% relative humidity at temperatures between 59 and 81°F to germinate and grow. High humidity must be present for at least 10-12 hours/day. Unfortunately, most plant disease-causing fungi also grow best at these same temperature and humidity ranges. Fungicides used to control the plant disease-causing fungi would probably also kill any beneficial fungi present. Insecticides may also be harmful to V. lecanii.

Least-toxic pesticides used against aphids in greenhouses include insecticidal soap (M-Pede™), horticultural oil (UltraFine SunSpray spray oil™), and botanical insecticides such as neem (Azatin™, Neemazad™, and Neemix™), or natural pyrethrums. See Appendix 2: Biorational Pesticides for more information and suppliers.

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Insect Growth Regulators

Insect growth regulators (IGRs) are another least-toxic pesticide control option for pests. IGRs typically kill insects by disrupting their development. They have a complex mode of action that precludes insects from rapidly developing resistance. IGRs can work in one of several ways:

  1. they can mimic juvenile hormones, so that insects never enter the reproductive stage of development;
  2. they can interfere with the production of chitin, which makes up the shell of most insects; or
  3. they can interfere with the molting process.
Photo Courtesy of Hecules Inc., Handbook of the Insect World 60p. Wilmington, DE

IGRs usually work through ingestion, so good spray coverage is essential. They generally don't affect non-target species, such as humans, birds, fish or other vertebrates. For most IGRs there are minimal re-entry restrictions. IGRs typically take several days to have an effect on pest populations. Because IGRs do not affect mature insects, adult beneficials released into the greenhouse after an IGR application are not likely to be affected. Use of IGRs is generally prohibited by organic certification organizations because the products are synthesized.

IGRs can sometimes be used in conjunction with biological control efforts and may provide growers with a "safety net" should beneficials fail to keep the pests below economically damaging levels. The table below lists some well-known insect growth regulators. (Contact information for suppliers is listed at the end of this document.)

Table 1. Selected Insect Growth Regulators
Brand Name Supplier Active Against
Azatin Hydro-Gardens, Olympic Horticultural Products whiteflies, leafminers, thrips, mealybugs, fungus gnats, aphids, cabbage loopers, diamondback moths, armyworms
Enstar II Wellmark Intl. whiteflies, fungus gnats, aphids, soft and armored scales, mealybugs
Neemazad Thermo Trilogy whiteflies, leafminers, thrips, mealybugs, fungus gnats, aphids, cabbage loopers, diamondback moths, armyworms
Neemix Thermo Trilogy whiteflies, leafminers, thrips, mealybugs, fungus gnats, aphids, loopers, diamondback moths, armyworms, cabbage loopers
Preclude Whitmire Micro-Gen whiteflies, thrips, scales, aphids

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Summary and Further Resources

Greenhouse aphids are tiny insects, but they demand serious attention on the part of the greenhouse grower. Integrated pest management offers a sustainable approach for dealing with greenhouse aphids, and safer pest control products facilitate the adaptation of least-toxic control measures that dovetail very nicely with the IPM philosophy. In the resources sections below, growers are provided with a list of biological control suppliers; and tables that summarize biocontrol agents and biorational pesticides that control aphids.

Related ATTRA Materials

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1) Lindquist, Richard. 1991. A guide to aphid control. GrowerTalks. October. p. 75.

2) Sunderland, Keith et al. 1992. Integrated pest management of greenhouse crops in Northern Europe: Aphids. p. 23-30. In: Jules Janick (ed.) Horticultural Reviews: Vol. 13. John Wiley and Sons, Inc. New York, NY.

3) Heinz, K.M. 1998. Dispersal and dispersion of aphids and selected natural enemies in spatially subdivided greenhouse environments. Environmental Entomology. Vol. 27, No. 4. p. 1029-1038.

4) Anon. 1999. Efficacy of four biocontrol agents on the green peach aphid, Myzus persicae, in greenhouse peppers. Midwest Biological Control News. January-February. p. 7.

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Biological Control Suppliers

A-1 Unique Insect Control
5504 Sperry Drive
Citrus Heights, CA 95621
916-967-7082 fax

PO Box 4247 CRB
Tucson, AZ 85738
520-825-2038 fax

Beneficial Insectary
14751 Oak Run Rd.
Oak Run, CA 96069
530-472-3523 fax

Caltec Agri-Marketing Services
PO Box 576155
Modesto, CA 95357
209-575-0366 fax

Florikan ESA Corp.
1523 Edger Place
Sarasota, FL 34240
941-377-3633 fax

The Green Spot, Ltd.
93 Priest Rd.
Nottingham, NH 03290-6204
603-942-5027 voice mail

Harmony Farm Supply
3244 Hwy. 116 No. F
Sebastopol, CA 95472
707-823-1734 fax

Hot Pepper Wax, Inc.
305 Third St.
Greenville, PA 16125
724-646-2302 fax

Hydro-Gardens, Inc.
PO Box 25845
Colorado Springs, CO 80932
719-531-0506 fax

International Technology Services Inc.
PO Box 19227
Boulder, CO 80308-2227
303-473-9143 fax

IPM Laboratories
PO Box 300
Locke, NY 13092-0099
315-497-3129 Fax

Koppert Biological Systems
2856 Main St. South
Ann Arbor, MI 48103
313-998-5557 fax

M&R Durango, Inc.
PO Box 886
Bayfield, CO 81122
970-259-3857 fax

Mycogen Crop Protection
5501 Oberlin Dr.
San Diego, CA 92121
619-453-9089 fax

Mycotech Corp.
PO Box 4109
Butte, MT 59702-4109
406-782-9912 fax

Natural Pest Controls
8864 Little Creek Dr.
Orangeville, CA 95662
916-726-0855 fax

Nature's Control
PO Box 35
Medford, OR 97501
541-899-9121 fax

Olympic Horticultural Products
PO Box 1885
Bradenton, FL 34206-1885
888-647-4329 fax

Rincon-Vitova Insectaries, Inc.
PO Box 1555
Ventura, CA 93002
805-643-6267 fax

SePRO Corp.
11550 N. Meridian St., #180
Carmel, IN 46032-4562
317-580-8290 fax

Soil Technologies Corp.
2103 185th St.
Fairfield, IA 52556
515-472-6189 fax

Stoller Enterprises, Inc.
8582 Katy Freeway, Suite 200
Houston, TX 77024
713-461-4467 fax

Wellmark International
1000 Tower Lane, Suite 245
Bensonville, IL 60106
630-227-6065 fax

Whitmore Micro-Gen
3568 Tree Court Ind. Blvd.
St. Louis, MO 63122

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Appendix 1: Beneficial Organisms

Organism Supplier Pests Controlled Application/Comments
Amblyseius degenerans or Iphiseius degenerans (predatory mite) Intl. Technology Services, IPM Labs., Green Spot aphids  
Aphidius colemani (parasitic wasp) Florikan, IPM Labs., Harmony Farm Supply, Praxis, Rincon-Vitova, Green Spot aphids Release .5-2/sq. yd.; humidity should be 70-85%, temp. 65-77F. Release at first sign of pests and for 3 consecutive weeks thereafter. Sensitive to pesticides.
Aphidius matricariae (parasitic wasp) Arbico, Hydro-Gardens, Green Spot aphids 500-3000/A. Can be used in greenhouses all year long.
Aphidoletes aphidimyza (predator midge) Nature's Control, Intl. Technology Services, IPM Laboratories, Hydro-Gardens, Arbico, Praxis, Rincon- Vitova, Harmony Farm Supply, Green Spot aphids 1-3/10 sq. ft.; humidity should be 50-90%, temp. 60-80F. Release when aphids are first observed; release lower numbers for preventive control; apply every two weeks. Active at night; sensitive to daylength.
Chrysopa carnea (predator) Natural Pest Controls, Beneficial Insectary, Caltec, Arbico, A-1 Unique Insect Control, Praxis, Rincon-Vitova, Hydro-Gardens aphids, caterpillars, mealybugs, scales, spider mites, thrips, whiteflies 1 lacewing/5-30 aphids; 1000 eggs/200 sq. ft. Apply every 1-3 weeks as needed. May arrive as eggs, immatures, or adults.
Chrysoperla rufilabris (predator) Arbico, Beneficial Insectary, IPM Labs., A-1 Unique Insect Control, Nature's Control, Praxis, Rincon-Vitova see above  
Chrysoperla spp. (predator) M&R Durango, Florikan, Green Spot see above  
Coleomegilla imaculata (pink ladybird beetle) Arbico aphids, caterpillars, mites, scales, thrips, whiteflies 1/sq. ft.; shipped as larvae and eggs.
Cryptolaemus montrouzieri. (predator beetle) Arbico, Caltec, Intl Technology Services, IPM Laboratories, Natural Pest Controls, Nature's Control, Florikan, Harmony Farm Supply, Hydro- Gardens, Praxis, Rincon-Vitova, Green Spot aphids, mealybugs, soft scales 2-5/infested plant; humidity should be 70-80%, temp. 70-80F. Larvae are cannibalistic; repeat as necessary for control; do not wear white while distributing.
Deraeocoris brevis (predator) Green Spot aphids, whiteflies, thrips  
Diaretiella rapae aphids (parasite) Arbico, Praxis aphids Release rates vary.
Harmonia axyridis (Asian lady beetle) Green Spot scale, whiteflies, mealybugs, aphids Temps. should be 70-85F; humidity around 70%.
Hippodamia convergens (lady beetle) (predator) A-1 Unique Insect Control, Arbico, Caltec, IPM Laboratories, Natural Pest Controls, Nature's Control, Harmony Farm Supply, Hydro-Gardens, Praxis, Green Spot aphids, mites, whiteflies Release at dusk near an immediate food source. Spray plants with water prior to release.
Iphiseius degenerans or Amblyseius degenerans (predatory mite) Intl. Technology Services, IPM Labs., Green Spot aphids  
Lysiphlebus testaceipes (parasitic wasp) Praxis aphids  
N. cucumeris and N. barkeri Hydro-Gardens thrips, aphids, mites 1 predator/sq. ft.; humidity should be moderate, temp. 70F. Establish population early. Repeat every month during periods of warm, dry weather.
Orius insidiosus (minute pirate bug) (predator) Florikan, IPM Labs., Harmony Farm Supply, Arbico, Hydro-Gardens, Praxis, Koppert, Intl. Tech. Services, Green Spot aphids, caterpillars, thrips, whiteflies, mites 1/10 sq. ft. (preventive), 1 every 2 sq. ft. when pests are present. Temperature should be 70-90F. Orius are dormant September-April. Re-apply every 2-3 weeks. Very susceptible to pesticides. Works well in combination with Neoseiulus cucumeris.
Propylea quatuordecimpuncata (predatory beetle) Praxis aphids  

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Appendix 2: Biorational Pesticides

Azadirachtin—extract of neem seed; IGR that works through contact or ingestion

Brand Name Supplier Pests Controlled REI Application/Comments
Azatin Green Spot Aphids, caterpillars, fungus gnats, leafhoppers, leafminers, Western flower thrips, whiteflies, psyllids 4 hours Apply when pests first appear.
Neemazad Thermo Trilogy Aphids, caterpillars, thrips, greenhouse whitefly, leafminers, sweet potato whitefly, psyllids, leafhoppers 12 hours Cannot be applied through irrigation. Low rate can be used as a preventive.


Beauveria bassiana—fungus that works through contact; exposure to non-target insects should be avoided
Brand Name Supplier Pests Controlled REI Application/Comments
Naturalis-O SePro aphids, caterpillars, mites, psyllids, thris, whiteflies 4 hours Apply when insects first appear and repeat every 7-10 days. Need good spray coverage. Not compatible with other fungicides.
BotaniGard Mycotech giant whitefly, green peach aphid, black vine weevil, others aphids and whiteflies, thrips, leafhoppers, psyllids, white grubs 12 hours See above.


Garlic extracts

Brand Name Supplier Pests Controlled REI Application/Comments
Garlic Gard Soil Technologies repels aphids and other insects     
Garlic Barrier Green Spot repels aphids and other insects 4 hours Use late in the day. Can be mixed with fish oil or horticultural oil. Do not use in combination with bumblebees or honeybees.


Horticultural oil—includes dormant and summer superior oils

Brand Name Supplier Pests Controlled REI Application/Comments
All Season Green Spot aphids, mealybugs, scales, thrips, whiteflies, spider mites
4 hours
Use on sunny days to promote rapid drying and decrease chance of phytotoxicity. Not compatible with beneficials


Hot pepper wax—contains capsaicin, parrafin, and mineral oil

Brand Name Supplier Pests Controlled REI Application/Comments
Hot Pepper Wax Green Spot aphids, loopers, beet armyworms, mites, whiteflies, thrips, mealybugs, etc.
4 hours
Also contains herbal essential oils. Not compatible with beneficials.
Hot Pepper Wax Hot Pepper Wax, Inc. see above
0 hours


Insecticidal soap—contains potassium salts of fatty acids

Brand Name Supplier Pests Controlled REI Application/Comments
M-Pede Mycogen aphids, mealybugs, scales, thrips, whiteflies, spider mites
12 hours
Phytotoxicity is often a concern, epseically after repeated applications.
Safer Green Spot see above
4 hours
See above.
Insecticidal soap Olympic see above   


Neem oil—multi-purpose organic insecticide/fungicide/miticide; kills eggs, larval and adult stages of insects

Brand Name Supplier Pests Controlled REI Application/Comments
Trilogy 90EC Thermo Trilogy greenhouse whitefly, silverleaf whitefly, sweetpotato whitefly, thrips, whiteflies, leafminers, aphids, mites, psyllids, San Jose scale, scale, spider mites, downy mildew, powdery mildew, Alternaria, Botrytis, etc.
4 hours
Apply at first signs of damage. Repeat every 7-10 days as needed.
Triact 90EC Thermo Trilogy see above
4 horus
For ornamental crops only.


Soybean oil

Brand Name Supplier Pests Controlled REI Application/Comments
Golden Natur'l Spray Oil Stoller aphids, fungus gnats, lace bugs, leafminers, scales, mealybugs, spider mites, whiteflies
12 hours



Greenhouse IPM: Sustainable Aphid Control
By Lane Greer
NCAT Agriculture Specialist
Copyright © 2000 National Center for Appropriate Technology
Slot 53


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