POPULATIONS OF PHYTOSEIULUS-PERSIMILIS (ACARI, PHYTOSEIIDAE) AND ITS HOST, TETRANYCHUS-URTICAE (ACARI, TETRANYCHIDAE), ON RESISTANT AND SUSCEPTIBLE SOYBEAN CULTIVARS

The populations of a predaceous mite, Phytoseiulus persimilis Athias-Henriot, and its prey, the twospotted spider mite, Tetranychus urticae Koch, were examined on a resistant and a susceptible soybean, Glycine max (L.) Merrill, cultivar in the laboratory. Both predation and the resistant soybean cultivar reduced the phytophagous mite population, with the predation effect being the more pronounced. There was no indication of interaction of predation by P. persimilis and soybean cultivar on T. urticae mortality. When adequate prey were available, there was no indication of antibiosis on the predator population from feeding on prey reared on resistant plants. However, the P. persimilis population was reduced at the lowest prey density examined from lack of prey and subsequent cannibalism.