Management of Onion Thrips (Thysanoptera: Thripidae) on Cabbage by Using Plant Resistance and Insecticides

Abstract

Control of Thrips tabaci Lindeman was evaluated using insecticides and host plant resistance. In 7 insecticide trials conducted from 1987 to 1996, using a total of 17 different insecticides, insecticide applications reduced thrips damage in only 2 of the trials. In 8 plant resistance trials conducted from 1985 to 1993 using >300 varieties or inbreds, some plant lines significantly reduced thrips injury in each trial. A 1996 trial testing variety and insecticide together found that both factors significantly affected thrips damage, although their interaction was not significant. Insecticide treatments in the 1996 experiment were unnecessary for the more tolerant varieties but helped reduce damage to acceptable levels in many of the moderately susceptible cultivars. In the highly susceptible varieties, we concluded that even the frequent application of insecticides was not sufficient to keep thrips damage at acceptable levels. Planting tolerant varieties, however, is a reliable way to keep thrips damage at low levels, even without insecticides.