Eastern Flower Thrips in Strawberries – Facts for Fancy Fruit

Eastern Flower Thrips in Strawberries

I received a report this week from a strawberry grower that overnight he went from no eastern flower thrips to an average of 15 thrips per bloom. Eastern flower thrips are an occasional pest of strawberries. They are attracted to and feed on flowers, with the result being leathery fruit or fruit that fail to ripen. This problem occurs every year at low levels but has not been serious in recent years, with the last serious problem in 1994. The numbers reported would indicate the possibility of serious problems this year. Eastern flower thrips do not overwinter in Indiana and must migrate northward each year on winds from the South. It is likely that thrips migrate on the same winds that move potato leafhoppers, so if you see leafhoppers there is a likelihood that thrips will also be present. Eastern flower thrips are very tiny, 1/16 inch long, so they are barely visible with the naked eye. I encourage all strawberry growers to be scouting for thrips in their blooms now. There are a couple of ways to sample for them. My favorite is to pick a flower and swish it around in a vial of alcohol. You can also shake the flowers over a white piece of paper or plate. If you find 2-10 thrips per flower, you should probably treat. Brigade and Danitol will provide excellent control and Entrust and Radiant will both provide good control. All of these products are moderately or highly toxic to pollinators that will be visiting your flowers, so you should treat as early in the bloom period as possible and apply the insecticides in the evening after pollinators have left the field.


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