J. Agric. Entomol. l(}(3):197-203 (July 1993) ABSTRACT Based on data from apple trees without the presence of any predatory mites, the effect of the pyrethroid lambdacyhalothrin on population density of the twospotted spider mite, Tetranychus urticae Koch, is reported. Results show that significantly (P < 0.05) higher numbers of T. urticae were found in pyrethroid·treatcd trees relative to the ...