Biology of Cowpea Flower Thrips and Host Plant Resistance

Abstract

Biology of cowpea flower thrips Megalurothrips sjostedti, was studied under field conditions. Population studies showed that the trend of thrips populations was closely tied with the flowering cycle of the cowpea crop. Peak thrips populations coincided with peak flowering of the crop. The seasonal abundance of thrips was mainly governed by weather factors. Thrips were found to oviposit mainly in the calyx of the cowpea flower. Evaluation of different sampling methods for thrips on cowpea indicated that water traps were most consistent. An artificial infestation method was developed for evaluating resistance of cowpeas to flower thrips in the screenhouse. Comparative yield studies without protection against flower thrips revealed a superior performance of cowpea cultivar TVx 3236 over other cultivars. The first phase of a negative field screening of cowpea germplasm showed that further sources of resistance to flower thrips were apparent in some accessions.