WSU Extension

Hortsense

Caption: Thrips damage on pea
Photo by: A.L. Antonelli
  
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Bean : Thrips
(revision date: 3/10/2017)


Biology
Thrips are tiny (1/20" or less), elongate, yellowish to dark insects. They typically feed in flower buds and blossoms. Thrips feeding can cause buds to fail to open. Blossom drop may also occur. Thrips can often be found by firmly tapping flowers into the palm of the hand and looking for the tiny yellowish insects. They are seldom a serious problem on beans.
Management Options

Non-Chemical Management
  • Predacious thrips, green lacewing larvae, and minute pirate bugs are important predators of plant-feeding thrips. Avoid use of broad-spectrum insecticides which kill these and other beneficial insects.
  • Control weeds, which can be important hosts for plant-feeding thrips.
Select non-chemical management options as your first choice!

Chemical Management


Apply when thrips are present.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Bonide Captain Jack's Deadbug Brew R-T-U [Organic]
    Active ingredient: spinosad (spinosyn A+D)  |  EPA reg no: 4-472
  • Bull's-Eye Bioinsecticide
    Active ingredient: spinosad (spinosyn A+D)  |  EPA reg no: 62719-314-56872
  • Safer Brand BioNEEM Multi-Purpose Insecticide & Repellent Conc [Organic]
    Active ingredient: azadirachtin  |  EPA reg no: 70051-6-42697
  • Safer Brand Insect Killing Soap Conc II [Organic]
    Active ingredient: potassium laurate  |  EPA reg no: 42697-60
  • This list may not include all products registered for this use.
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Caption: Thrips damage on pea
Photo by: A.L. Antonelli
Caption: Thrips
Photo by: Unknown