EAST LANSING, Mich. — Michigan State University Extension entomology specialist for ornamentals David Smitley has released his “2017 Greenhouse Insect Management” document. These are the recommended products to control thrips, aphids, whiteflies, spider mites, broad and cyclamen mites, fungus gnats, mealybugs and Florida fern caterpillar.
MSU Extension plant pathologist Mary Hausbeck has released her new “Greenhouse Disease Management 2017 Season” recommendations. The products are classified as either “A” or “B” team products. The “A” team products provide the best control for the diseases, and “B” team products are those that provide control and are good to include in a spray rotation. In addition to the overall disease management recommendations, Hausbeck has also released the “2017 Greenhouse Impatiens Downy Mildew” recommendations. This document provides a rotation of products that are effective in preventing impatiens downy mildew. It provides information on the rates and frequency of the products listed.
Resistance management is a very important issue facing not only individual growers, but the industry as a whole. In order to prevent disease and insect resistance, always remember to rotate modes of action in a disease or insect management program. For example, growers should be extra careful when managing western flower thrips and twospotted spider mites. These insects are greenhouse pests that can develop resistance easily.
With respect to disease, there has been documentation of strains of Pythium found in Michigan greenhouses that are resistant to mefenoxam (Subdue MAXX). Growers should be documenting rates and timing of pesticide applications and be making notes on efficacy.
If you suspect you have a disease or insect that is resistant to insecticides or fungicides, please contact your local MSUExtension greenhouse educator.