Abstract

This study was designed to evaluate the potential effects of acetochlor (herbicide) on the survival and avoidance behaviour of lycosid spiders example Lycosa terrestris. During the topical toxicity experiment, P. birmanica was found to be more susceptible to acetochlor than L. terrestris. Although, there was 10% mortality at field rate concentration by topical exposure, we did not observe any mortality during residual toxicity experiment for both spider species even at double field rate concentration. There was no difference in the time spent by both species on the herbicide or water treated part of filter paper. It was concluded that use of acetochlor at the recommended rate in the agricultural field is safe for tested spider species, which are important biological control agents in the study area.

Key words: Herbicide, residual toxicity, acetochlor.