Abstract: The toxicity of five insecticides, azadirachtin, imidacloprid, endosulfan, biphenthrin and DDVP, on predatory mite (Anystis baccarum L), and effects on the functional response of A. baccarum mite in preying the tea leafhopper (Empoasca vitis (Göthe)) were investigated. Results revealed that, in contrast to other kinds of insecticide, azadirachtin, imidacloprid showed a rather weak toxicity and less influence on the predation function of A. baccarum mite; the functional response model of A. baccarum mite preying on tea leafhopper were all conformed to Holling’s type II curve in spite of pretreated with sublethal doses of these insecticides. However, there were some changes in the parameters of the model, e.g., the maximal predatory capacities of A. baccarum mite that pretreated with sublethal dose of insecticides were reduced, the handling time was prolonged, the predatory rates were declined, and the searching capability were weakened than that of control. These findings suggested that insecticides at sublethal level had harmful influence on the predation of A. baccarum mite.

Key words: Anystis baccarum L., Empoasca vitis Göthe;, predation, insecticides, sublethal effect, ecotoxicology