Managing rotation of biopesticides to control onion thrips, Thrips tabaci, in the lower Columbia Basin

Onion thrips, Thrips tabaci Lindeman, is a polyphagous pest that causes serious damage on vegetables and ornamentals around the world. Onion thrips is an especially important pest on Alliaceae plants such as onions (Allium cepa L.) and leeks (Allium porrum L.). A study on the economic impact of onion thrips damage in the absence of control measures indicates that the pest could reduce onion yield. Year after year, onion growers in Oregon and Washington are facing a pest that poses significant management challenges without adding the effect that the thrips are able to transmit IYSV. The objectives of this study are (1) to evaluate biopesticides that would effectively control onion thrips; (2) to evaluate rotation of biopesticides with a conventional standard that would effectively control onion thrips in the Columbia Basin. In this study, we demonstrated the efficacy of biopesticides for onion thrips management by quantifying the reduction of thrips population and by measuring the direct effect of thrips numbers on yield. Utilization of biopesticides for thrips management would reduce insecticide resistance selection pressure, increase environmentally friendly management, and increase workers safety conditions.