Pepper, grapes, melon, chrysanthemum, strawberry, peas, peanuts, watermelon, plums, nectarines, peach, cotton, tomato, cucumber, basil, eggplant, cabbage, cauliflower, beans, and a large group of ornamental plants
Western flower thrips are small, polyphagous insects (adults are 1.2 mm in length). They are a major pest in the world of agriculture with several hundred different host plants. They can usually be found on the upper parts of plants, especially inside the flowers, where they feed on pollen. Western flower thrips undergo partial metamorphosis, developing through several distinct stages, including egg, larva, pupa and adult-which can fly only weekly.
They can cause damage to crops directly from scarring of fruits (as a result of feeding or laying eggs in the plant’s tissue) and indirect damage from the role it plays as a vector of viruses, responsible for TSWV (tomato spotted wilt virus; the most economically important), TCSV (tomato chlorotic spot virus), INSV (impatiens necrotic spot virus), GRSV (groundnut ringspot virus) transmission.
Growing inside structures: The most effective way to protect your crop from thrips is simply (but costly) growing it inside a greenhouse or a dense (50 Mesh) net structure.
Monitor the field regularly, and gently shake foliage or flowers onto a bright colored sheet of cardboard occasionally. Count the number of thrips that fall onto the sheet and make an estimation for levels of infestation.
Thrips are attracted to bright floral colors; take advantage of this and use sticky traps that lure and capture, which can help with monitoring.
Sanitation: Try keeping your crop’s close surroundings and environmental conditions as neat as you can by removing weeds that thrips are especially attracted such as sinapis arvensis (“wild mustard”).
It’s hard to manage thrips effectively with insecticides. They have high maneuverability skills and their egg and pupa stages are protected, which makes it difficult. Another common issue that greatly reduces effectiveness of treatments is inadequate coverage when spraying contact insecticides.
Try to avoid using organophosphate, carbamates, or pyrethroids insecticides; they will effectively eliminate natural enemies and pollinators, while leaving most of the thrips population intact and unharmed.
Spinosad-based products are not cheap, but possibly the best insecticides available today that effectively combat thrips. Spinosad-based insecticide are fermented products of a naturally occurring bacterium, and certain formulations are organically acceptable. Keep in mind that combining horticultural oil with each spray application is essential and will increase overall effectiveness.
A successful commercially available natural enemies of thrips are of the genus Orius (“minute pirate bug”), omnivorous bugs in the Anthocoridae family.
*Names marked in red are considered to be highly poisonous to beneficial insects.
*Names marked in green are considered to be organic and IPM (integrated pest management) compatible.