By Tom Dudek, Michigan State University Extension
Greenhouse growers can access the latest MSU insecticide recommendations in a new resource. Eight major greenhouse insect and mite pests are covered, as well as information on growing bee-friendly plants.
Michigan State University Extension entomology specialist for ornamentals David Smitley has released his 2016 “Greenhouse Insect Management” document, which serves as recommendations for growers that need to control thrips, aphids, whiteflies, spider mites, broad and cyclamen mites, fungus gnats, mealybugs and Florida fern caterpillar. The guidelines also give information on how to start clean each year to prevent insects from overwintering in greenhouses, the importance and frequency of scouting for insects as well as notes on systemic insecticides, neonicotinoids and pyrethroid insecticides.
Smitley has also added a section on practices that contribute to growing bee-friendly plants that include:
- Do not spray flowers in the last two to three weeks before shipping.
- Do not apply soil drenches of imidacloprid or other neonicotinoids to types of plants that are attractive to bees. Very few annuals are attractive to bees. However, the following annuals are attracted to bees: ageratum, snap dragons, calendula, cosmos, dahlia and zinnia. Many perennials are attractive to bees, and a list of them will be made available to you soon.
- Do not use imidacloprid soil drenches on flowering trees and shrubs that are attractive to bees.
- Read bee warning information on pesticide labels and avoid practices that are harmful to bees.
For more assistance in managing your greenhouse insect pest issues, contact your local MSU Extension greenhouse educator.