Insects & Diseases

IPM Defined:  "IPM is a sustainable approach to managing pests by combining biological, cultural, physical and chemical tools in a way that minimizes economic, health, and environmental risks."

IPM  Pest management, not eradication, is the goal.  Manage pests below the economic threshold.

Economic Threshold  How would you define it?  The point at which the disease or pest infestation begins to diminish the quality of the crop.

Economic Thresholds  Thresholds should be quantitative and grower driven. For example, thresholds could be based on the average number of pests per trap each week. the percent of plants or leaves found to be damaged or infested during visual inspection. the number of pests dislodged per shake sample.

EIL ET Average density Time Pest density Economic Threshold Apply controls Avoid exceeding economic injury level

Economic Thresholds  Vary depending upon the crop.  Bacterial Leaf Spot on Poinsettia: Devastating!  Bacterial Leaf Spot on Greenhouse Tomatoes: Not such a big deal. Why?  Insects & diseases on ornamental crops grown in nurseries: Big deal? Yes or no?

Scouting and Record Keeping

 Also called “monitoring’.  Perform weekly.  In greenhouses focus monitoring near doorways, vents and fans.  1 card per 1,000 square feet. Yellow: attracts most flying insects Blue: for thrips  Replace cards on a regular basis.

Cultural IPM Tactics

Sanitation  The goal of sanitation is to eliminate all possible sources of the pest. weed removal inside and outside the greenhouse. ○ grass flowering-increase in thrips population weed removal around nurseries. dispose of dead/diseased plants. In greenhouses: ○ quarantine infested plants in a separate room. ○ medium pasteurization (especially if it contains soil). ○ algae control-fungus gnats.

Watering  Too much moisture: leaf diseases root rots fungus gnats algae  Too little moisture: stresses the plants and predisposes it to disease hot, dry conditions favor spider mites

Temperature  Plants begin to stress at temperatures of 95 degrees F. and higher.  Temperature fluctuations.

Growing Medium  Should have good aeration/drainage.  Monitor EC.

Variety Selection  Choose insect/disease resistant varieties.  If possible, rotate crops.

Physical/Mechanical IPM Tactics

Insect Screening

Biological IPM Tactics  The use of living organisms to control pests.

Lady Bugs

Parasitic Wasps

Predatory Mites

Chemical IPM Tactics:  Biorational Pesticides  Conventional Pesticides

Biorational Pesticides:  Insecticidal Soaps  Horticultural Oils  Bacillus thuringiensis-bacteria  Beauveria bassiana-fungus that infects the chitin exoskeleton of many pests  Diatomaceous Earth  IGR’s kill insects by disrupting their development

Conventional Pesticides  Licensed Applicator  WPS  Re-entry Times  Residue  Resistance rotate between groups/active ingredients

Major Insect Pests of Greenhouse-Grown Bedding Plants:

 Aphids  Thrips  Fungus Gnats  Whiteflies  Shore Flies  Leafminers  Mealybugs  Spider Mites

Aphids

Immature & Adult Greenhouse Thrips

Thrips Life-Cycle

Greenhouse Whiteflies

Mealybug excreting honeydew

Two-spotted Spider Mite Red Spider Mite

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