Greenhouse Integrated Pest Management
What is Integrated Pest Management?
Integrated Pest Management (IPM) is a holistic approach to managing insects, diseases, weeds and cultural problems in the greenhouse. It is the use of a variety of different pest management tactics including cultural, biological, physical, mechanical, and chemical controls. Frequently, two tactics, such as cultural and biological controls, are combined to ensure a successful pest management program. Pest management decision making is based upon information gathered from a regular monitoring program. Weekly, regular inspection of plants enables you to detect potential problems early before they develop into serious problems.
Some of the components of an IPM program include:
Before introducing a crop, evaluate the entire greenhouse for the presence of potential problems. Note the presence of “pet plants”, weeds, algae, and growing media debris especially underneath benches, because these provide a refuge for many greenhouse pests. Prevention of pests is easier if you identify, analyze and correct existing problems before plants are introduced.
Many insects and diseases can be accidentally introduced into a greenhouse when infested cuttings, plugs, or plants are introduced. Inspect incoming plant material for the presence of insects and diseases and evaluate their general plant health and quality, as well. If feasible, isolate infested plants in a separate greenhouse or growing area.
Cultural Controls and Sanitation
Cultural control is the key to a successful IPM program. By providing the proper environmental conditions (light, water, temperature and nutritional levels), you can insure high quality crops. Regular monitoring of soluble salt levels and pH of the growing media will help develop a successful nutritional program. Over fertilization of plants, especially with nitrogen, encourages the development of aphids, whiteflies, mealybugs and spider mites. The resulting lush plant growth is more susceptible to foliar diseases such as Botrytis blight and Rhizoctonia web blight. High soluble salt levels and the incorrect pH can encourage Pythium root and stem rot.Overwatering encourages the development of Pythium and other root rot diseases.
A clean greenhouse helps to prevent many potential pest problems. Keeping the walkways and areas under the benches free of spilled potting media, weeds and debris can help prevent many insect and disease outbreaks. Disinfecting benches and walkways between crops will help to minimize disease spread. Discard heavily infested plants into garbage containers with tight sealing lids to prevent winged insect pests from migrating back into the crop. Keeping the hose ends off the floor will help prevent many root and stem diseases. The cull pile should be kept as far from the greenhouse as possible in order to discourage reentry of winged insect pests and disease spores.
Proper spacing of plants will promote healthy growth and discourage the development of foliar diseases such as Botrytis blight. Disease suppressive mixes and biological fungicides are being used successfully by many growers. Growers are more likely to be successful in using biological controls if they are integrated with proper cultural controls and a regular, consistent monitoring program.
Gathering information on the biology and life history of key pests is critical to insure effective decision making. Some selected references are listed at the end of this fact sheet. Additional information is also available on the Internet.
Developing a Monitoring Program
By thorough, consistent scouting, you can detect potential problems early and gather current information on the identity, location and causes of pest problems.Consistent scouting will also enable you to evaluate the effectiveness of the biological control agents released. In Connecticut, the Greenhouse IPM Program focuses on intensive hands-on educational training throughout the season. The goal is to provide growers with the knowledge, skills, experience and confidence needed to achieve effective implementation of IPM.
Who Should Scout?
Employees can be trained to scout or growers can do their own scouting. Some of the advantages of in-house monitoring include: familiarity with the greenhouse and its crop production practices and the ability to promptly inspect incoming plant material. However, scouting must be considered a high priority to ensure inspections on a weekly or as needed basis. Adequate time and personnel need to be assigned this important activity to insure that other, more routine greenhouse tasks do not interfere with scouting.
Growers may also hire private pest management consultants. Some of the advantages of private consultants include their ability to scout quickly and efficiently, and their specialized up-to-date knowledge of pest management.
Some Useful Scouting Tools
How to Scout
A monitoring program consists of the use of sticky cards, random plant inspections and the selection of pest-infested plants to be used as indicator plants. Petunias or fava beans can also be used as indicator plants to monitor for the presence of thrips carrying tospoviruses (impatiens necrotic spot virus. (INSV) or tomato spotted wilt virus (TSWV)). You may adapt the following suggestions to your individual greenhouse operations.
Using Sticky Cards
Yellow sticky cards can be used to detect infestations of adult whiteflies, fungus gnats,leafminers, shore flies, thrips and winged aphids. Place at the minimum rate of one card per 1,000 square feet. Space the cards equally throughout the entire range in a grid pattern. Place additional cards near entrances and vents to detect insect migration from the outside. Check and change the cards weekly to detect pest population trends. Record the approximate numbers of adult whiteflies, leafminers, thrips, aphids, fungus gnats and shore flies in additional to any other insects caught on the cards. Over time, you can correlate the number of insects found on the cards to the pest damage on the crops to develop your own tolerance level for pest activity.
Scouting Route in the Greenhouse
Many insect pests, including whiteflies and spider mites, tend to be densely aggregated. Therefore, random plant inspection is needed to locate the various infestations. Based upon your past experiences, focus on inspecting those species or cultivars that are more prone to insect, mite infestations as well as diseases. For each area of 4,000 square feet, samples should be taken from at least five to ten random sites. Moving in an "M", or zigzag shaped pattern provides good sampling coverage. Closely inspect potential problem areas, such as the middle of the bench which may have received less spray coverage or the ends of the benches where there may be less air circulation. Inspect hanging baskets and any crops grown on the floor. While scouting, note the presence of diseased plants or weeds to be removed, or any cultural or environmental controls that need to be implemented. Select and tag pest-infested plants to be used as indicator plants to track population development and evaluate treatment effectiveness.
When visually inspecting plants, first consider their general health and vigor. Closely examine plants that show unusual growth patterns or appear to be under stress. Inspect leaves, stems and roots. Closely examine roots to look for signs of root decay or fungus gnat feeding. Healthy roots should be white and actively growing.
Record Keeping System
Develop a record keeping system that will aid in effective decision making. Keep records of sticky card counts, weekly monitoring, treatments applied and treatment effectiveness. Specific forms (Provide link to forms here) or a small notebook may be used. Making graphs of population trends helps in decision making.
Keep complete records of the product name of the pesticide used, the product's EPA registration number, the total amount applied, and the size of the area treated, the crop on which the pesticide was applied, and the date and location of the application.
USDA Pesticide Record Keeping Form for Private Applicators See link below
Private Applicator Pesticide Use Summary Report – CT DEP
Pest Management Decision Making
Each week, the grower and scout should review the scouting information gathered from sticky card counts, plant inspections, and data from indicator plants. This data will help prioritize a strategy. Looking at trends over a period of time will help decide if controls are needed.
See the reference list below for additional information.
By Leanne Pundt, Extension Educator, Commercial Horticulture, Revised December 2010
Casey, C. Ed. 1997. Integrated Pest Management for Bedding Plants. A Scouting and Pest Management Guide. Cornell Cooperative Extension Publication No. 407. 109 pp.
Cloyd, R. 2007. Plant Protection. Managing Greenhouse Insect and Mite Pests. Ball Publishing. Batavia, IL. 88 pp. Daughtrey, M. & A. R. Chase. 1992. Ball Field Guide to Diseases of Greenhouse Ornamentals. Ball Publishing, Bativa, Ill. 218 pp.
Gentile, A. G. & D. T. Scanlon. 1992. A Guide to Insects and Related Pests of Floricultural Crops in New England. Revised by T. Smith. 36 pp.
Pundt, L. 1997. New England Integrated Pest Management Scouting Guide for Poinsettias: A Manual for Growers and Scouts. University of Connecticut Cooperative Extension System. 30 pp.
Stack, Lois Berg. (Editor). New England Greenhouse Floriculture Guide. A Management Guide for Insects, Diseases, Weeds and Growth Regulators. New England Floriculture Inc and the New England State Universities. Available from: New England Greenhouse Conference (www.negreenhouse.org) or from available from: Univ. of Conn., College of Agriculture and Natural Resources, Office of Communications, Resource Center, 1376 Storrs Rd, Unit 4035 Storrs, CT 06269-4035.
Thomas, C. 2005. Greenhouse IPM with an Emphasis on Biocontrol. Publication No. AGRS-96. 89 pp. Pennsylvania Integrated Pest Management Program. http://extension.psu.edu/ipm/resources/pestproblemsolver/greenhouse/greenhouseipm/view
This information was developed for conditions in the Northeast. Use in other geographical areas may be inappropriate.
The information in this material is for educational purposes. The recommendations contained are based on the best available knowledge at the time of printing. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. The Cooperative Extension system does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available.All agrochemicals/pesticides listed are registered for suggested uses in accordance with federal and Connecticut state laws and regulations as of the date of printing. If the information does not agree with current labeling, follow the label instructions. The label is the law.Warning! Agrochemicals/pesticides are dangerous. Read and follow all instructions and safety precautions on labels. Carefully handle and store agrochemicals/pesticides in originally labeled containers immediately in a safe manner and place. Contact the Connecticut Department of Environmental Protection for current regulations.The user of this information assumes all risks for personal injury or property damage.Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Kirklyn M. Kerr, Director, Cooperative Extension System, The University of Connecticut, Storrs. The Connecticut Cooperative Extension System offers its programs to persons regardless of race, color, national origin, sex, age or disability and is an equal opportunity employer.