Interactions in the Tritrophic System 'Host Plant-Spider Mite Tetranychus urticae Koch (Acarina, Tetranychidae)-Predatory Midge Feltiella sp. (Diptera, Cecidomyiidae)' on Cucumber Cultivars

摘要

A study of interspecific relations in the tritrophic system "plant-spider mite-predatory gall midge Feltiella sp." on cucumber cultivars differing in their resistance to the phytophage has shown that the formation and functioning of the consortium arelargely influenced by genetic properties of the plant and ecological features of the consorts. The nature of ecological association of the predator and its prey in the tritrophic system appears to depend on the cucumber genotype and on the morphologicaland physiological state of the plant. It has been shown that at different densities of the spider mite on cucumber plants, the predator increases the plant resistance by reducing the pest density, while genetic resistance of the plant restricts the phytophage densities thereby increasing the efficiency of the acariphage.