Western Flower Thrips on Table Grapes in Southern Italy

Abstract

In 1992 observations on western flower thrips (WFT) were made in curtain reared vineyards of Apulia (Southern Italy). During winter WFT was not found in soil or under the stump bark, but overwintered on wild and cultivated blooming plants. In May, populations increased on blooming citrus, olive plants and greenhouse crops, then migrated into neighboring vineyards. On grape-vine, WFT appeared soon after sprouting and were almost simultaneously caught on the colored sticky traps. Females reached a peak during fruit-setting, while larval stages peaked 3 wk later. In mid-June females migrated from the vines to other blooming plants. Adults and larvae disappeared as the grapes ripened. A light infestation was seen from the end of July to mid-September. The highest number of thrips on the traps was recorded shortly after the adult peak on the vine. Blue traps caught 3 times more thrips than yellow ones. The sex ratio favored females until fruit setting, then males predominated in the first half of August and at harvest.