Studies on the interactions among Phaseolous vulgaris, Tetranychus urticae and Amblyseius fallacis

Key Words：Amblyseius fallacis, Tetranychus urticae, Phaseolous vulgaris, selectivity, volatile substance

Abstract：  The relative preferences of Amblyseius fallacis (Garman) for healthy host plants, mechanically injured host plants and host plants infested with the spider mite Tetranychus urticae (Koch) were determined using a Ytube olfactometer and leaf disc test. The composition and relative contents of the volatiles of healthy, mechanically injured and mite infested Phaseolous vulgaris host plants were analyzed and identified by gas chromatographymass spectra (GC/MS). The results showed that odors from the leaves plants that had, or were, infested with T. urticae, which included plants with mites and their feces, plants without mites but with their feces and plants without mites or their feces, were significantly more attractive to A. fallacis than either mechanically injured or healthy plants. A. fallacis could be attracted by the odors from mechanically injured plants and healthy plants to which T. urticae feces had been added, but showed a greater preference for odors from miteinfested plants. The composition and content of volatiles differed significantly between healthy, mechanically injured and miteinfested plants. The volatiles of plants infested with T. urticae had more components than those from mechanically injured or healthy plants, and were of higher molecular weight. Methoxyphenyloxime, 2,4-di-tert-butylphenol, (E,E)-α-farnesene, junipene and alkyl comprised the greater proportion of the volatiles collected from all three kinds of plants.