Management of Insects and Mites in Greenhouse Floral Crops

Insect and mite pests of greenhouse crops present unique challenges with respect to their management and control. Plants are frequently moved in and out of the greenhouse, creating opportunities for repeated introduction of pests. Crops are grown year-round in a protected environment that is favorable for pest development. Additionally, greenhouse pests often exist in the absence of their natural enemies unless predators and parasitoids are intentionally introduced.

Many greenhouse pest populations can be reduced by implementing and following a comprehensive integrated pest management (IPM) plan. At a minimum, such a plan should include the following:

 

• a regular pest monitoring program coupled with careful recordkeeping
• implementation of exclusion techniques and careful sanitation practices when handling new plants and growing media
• thoroughly cleaning the greenhouse after each production cycle
• keeping all openings into the greenhouse (doors, screens, ventilators) in good repair
• cultural practices such as mowing grass around the greenhouse to reduce pest harborages
• introduction and/or conservation of biological control agents when appropriate

 

Chemical pesticides can be part of a comprehensive IPM plan, but should not substitute for good horticultural practices, or be used as “preventative insurance” against pests. Such practices are rarely economically or environmentally justifiable, and provide a recipe for the selection of pests that are resistant to the pesticide. Pesticides should be applied using specified application methods to assure optimal control. It is especially important to follow all safety precautions when applying pesticides in a greenhouse due to its enclosed environment. Follow ALL label directions, especially all Worker Protection Standards. Pesticide recommendations in this publication are correct as of the “Modified Date.” Always check the label that came with the purchased pesticide for the most current application directions and restrictions. More information on greenhouse pest management can be found in the following Oklahoma Cooperative Extension Service publications:

• HLA-6707, Pesticide Use and Safety in the Nursery and Greenhouse
• HLA-6710, Integrated Pest Management in Commercial Greenhouses: An Overview of Principles and Practices
• HLA-6711, IPM- Scouting and Monitoring for Pests in Commercial Greenhouses
• E-1011, Arthropod Pest Management in Greenhouses and Interiorscapes

 

 

 

 

 

 

 

 

 

 

† Restricted Use Pesticide; you must be a certified (licensed) pesticide applicator to purchase and apply this product.

 

* The numbers associated with the IRAC class column were developed by the Insecticide Resistance Action Committee (IRAC). It is intended to help in the selection of insecticides for preventative resistance management. If you make multiple applications for a specific pest or group of pests during a growing sequence, simply select a registered insecticide with a different number for each generation (14-21 days). You can rotate within the same number if more than one subgroup is available (Example: 2A and 2B). To further delay resistance from developing, integrate other control methods into your pest management programs. See “MF-2905: Resistance Management” for further information. This publication can be found at http://www.ksre.ksu.edu/bookstore/pubs/mf2905.pdf.

** REI = Restricted Entry Interval (in hours); workers not allowed to enter into treated area until the REI has elapsed.

 

Notes:

1. Before purchasing and using any pesticide, read the label carefully for registered use(s), rates, and application frequency. Also note toxicity category on the label of each pesticide since toxicity ratings may affect reentry intervals and note any ventilation requirements. Wear protective clothing as recommended on each pesticide label.
2. When using horticultural oils it is important to not use oils with insecticidal soap or any sulfur containing compounds. Also, do not use horticultural oils in sprayers in which fungicides have been used. Frequent agitation is required when using horticultural oil sprays.
3. Insecticides with a broad spectrum of properties in the chemical classes pyrethroids, organophosphates, carbamates, and neonicotinoids may be harmful to natural enemies (parasitoids and predators). Some broad-spectrum insecticides are more selective than others, and selectivity further depends on how, when, and where the insecticide is applied. Be sure to check the label for the kinds of insects controlled by the product, or contact your county extension educator for information on the use of insecticides with natural enemies.