The effect of dichlorvos on control of drosophila and its safety evaluation under different application methods.

Drosophila is a common strawberry pest. In this work, toxicities of the 77.5% EC dichlorvos to 3rd instar larvae and adults of drosophila were evaluated through indoor bioassays and field bioassays, respectively. To insure the safety, dichlorvos dissipation and terminal residue in strawberry by different application methods under field conditions were determined by high-performance liquid chromatography. The decline curves of dichlorvos residues in strawberry corresponded with first-order kinetics, and dichlorvos dissipated rapidly in strawberry with half-life (t1/2) of 7.58-13.17 h. Terminal residues below the maximum residue limit of strawberry and soil in different distance were achieved after 24 h under different application methods. This article provides guidance to the proper and safe use of dichlorvos in agriculture; it is more reasonable that dichlorvos is applied by embedding on the ground near the strawberry plants covered plastic film with holes.