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, physical, mechanical, chemical and biological controls. Frequently, two tactics, such as cultural and biological controls, are combined. 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:
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.
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. 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 pests.
Before the crop is introduced, evaluate the entire greenhouse for the presence of potential problems. Note the presence of weeds, drainage problems, algae, debris under the benches or the presence of "pet plants." Prevention of pests is easier if you identify, analyze and correct existing problems before plants are introduced.
Cultural control is 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 is needed to develop a successful nutritional program. Over fertilization can result in lush plant growth that is more susceptible to aphids and other sucking insects. High soluble salt levels and the incorrect pH can encourage Pythium root and stem rot.
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 for use against certain soil borne diseases have recently become available.
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. Information is also available on the Internet.
By thorough, consistent scouting, you can detect potential problems early and gather current information on the identity, location and causes of pest problems. 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.
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.
A monitoring program consists of the use of yellow 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 impatiens necrotic spot virus. Growers may adapt the following suggestions to their individual greenhouse operations.
Yellow sticky cards can be used to detect infestations of adult whiteflies, fungus gnats, shore flies, winged aphids and thrips. 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, 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.
Many insect pests, including whiteflies and mites, tend to be densely aggregated. Therefore, random plant inspection is needed to locate the various infestations. Monitor key plants and key pests. Key plants are those plants with a high dollar value or those plants that have serious persistent problems year after year. Key pests are those pests that are serious year after year.
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 zig-zag, shaped pattern will provide 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 that will need to be removed, or any cultural or environmental controls that will 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. Closely examine the root system to determine if the roots are actively growing and healthy. Look for signs of root rots or larval fungus gnat feeding, too.
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 or a small notebook may be used. Making graphs of population trends may help in decision making. A year-end summary will also aid in planning. Keep complete records of the product name of the pesticide used, the product's EPA registration number, the total amount applied, the size of the area treated, the crop on which the pesticide was applied, and the date and location of the application.
Each week, the grower and scout should review the scouting information gathered from sticky card counts, plant inspections, 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.
Casey, C. Ed. 1997. Integrated Pest Management for Bedding Plants. A Scouting and Pest Management Guide. Cornell Cooperative Extension Publication No. 407. 109 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.
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.