Keeping thrips populations in check during the cool season will make later control efforts much easier. Warm weather means shorter life cycles, increased plant movement, and flowering of outside native plants and wildflowers. All of this adds up to increased thrips pressure and an opportunity for a population explosion. Growers should initiate a multistage control program targeted at controlling larvae, pupae and adult thrips. Contact IPM of Alaska for more information on screening greenhouse air vents and intakes.
Sanitation is key for controlling pests in greenhouses.
The goal of sanitation is to eliminate all possible sources of the pest. Weeds inside and near the outside of the greenhouse can harbor pests. It's best to pull the weeds inside the greenhouse rather than spray them, since thrips may survive the spray and migrate onto crops. Bag all weeds and dispose of them outside the greenhouse. Workers in the greenhouse should avoid wearing yellow clothing, since many pests are attracted to this color and may hitch a ride on the fabric from one greenhouse to the next.