Using Novel Cultural Controls for Management of Onion Thrips on Onions

Abstract

Onion thrips has been identified by onion growers as their major pest. In 2005, uncontrollable infestations of thrips were common because of the hot, dry weather combined with some populations having developed resistance to some commonly used insecticides. To enhance an IPM approach for this pest in onions, a non-insecticidal approach is needed. We have been focusing on using straw mulch and kaolin clay to reduce thrips populations while not interfering with common agronomic approaches. The NYS IPM Program provided partial support to look at the use of kaolin clay, and these studies were conducted in the laboratory. Kaolin clay reduced the ability of thrips to lay eggs, reduced egg hatch, reduced feeding on the plant, and reduced the number of larvae that could develop into adults. Field trials conducted with other funding sources indicated that spraying with kaolin clay resulted in reduced thrips densities. One concern with the use of kaolin sprays is that they may have to be reapplied when the residues are washed away with rain. However, kaolin clay can be part of an overall IPM program for thrips control on onions and help to reduce thrips damage to onions while reducing the use of harder insecticides.