Jerry Brust, IPM Vegetable Specialist, University of Maryland; jbrust@umd.edu
In several strawberry fields I have visited over the last two weeks I have found thrips in the flowers. Almost all of the thrips were eastern flower thrips. The number of thrips found in a flower varied from 0 to 10. Thrips were feeding on pollen and not on any part of the ovary. Though studies vary as to the number of thrips needed per flower before they are considered above threshold, the studies agree that 10 thrips/flower are needed before any treatment is justified. After the fruit begins to develop and there is little pollen left in the flower most thrips will leave the fruit. However, if the thrips do not leave they will begin to feed on the developing fruit and seeds, interfering with proper fruit development. Densities of 3-5 thrips/fruit can lead to fruit damage and thrips populations need to be closely watched during the first two to three weeks after fruit set.