Preference ofTetranychus urticae(Acari: Tetranychidae) for Kidney Beans Pre-Infested byFrankliniella occidentalis(Thysanoptera: Thripidae) and Possible Roles of Induced Bean Volatiles

Abstract

Abstract We tested the selectivity of the adult female two-spotted spider mite (TSSM), Tetranychus urticae, for kidney beans subjected to various treatments, which were infested by 2nd instar larvae of western flower thrips (WFT), Frankliniella occidentalis, at different densities (5, 10, or 15 WFT/plant) and time (2, 4, or 6 days). The volatiles released from beans subjected to various treatments were evaluated by gas chromatograph-mass spectrometry. We found that TSSM was more likely to select bean plants infested for 2 days when the density was 5 WFT/plant. TSSM preferred bean plants infested for 4 days when the density was 10 or 15 WFT/plant. Irrespective of the WFT density, TSSM had the lowest preference for healthy beans and beans infested for 6 days. When the WFT infestation duration was the same, the percentage of TSSM was greatest on beans infested with 10 WFT, and there were no significant differences among the other three bean plant treatments. The results indicated that TSSM tended to prefer b...