Differential Attractive Response of Bradysia impatiens Larvae to Volatiles from Fusarium solani-Infected Kidney Beans

초록

The fungus gnat, Bradysia impatiens Johannsen, is a primary root pest of plants, resulting in significant losses in crop production. Here, we evaluated the odor preference of 1st-2nd and 3rd-4th instar larvae on nine test materials (enoki mushroom [EM], king oyster mushroom [KOM], oyster mushroom [OM], white mushroom [WM], kidney bean [KB], potato [PTT], Fusarium solani [FS], F. solani-infected kidney bean [FSK], and cheonggukjang [CGJ]) using two- and multiple-choice bioassays. In two-choice bioassays, EM, KOM, OM, WM, KB, PTT, FSK, and CGJ attracted both 1st-2nd and 3rd-4th instar larvae of B. impatiens significantly more than the control. FSK attracted a high number of 1st-4th instar larvae when the results from both larval stages were combined. In subsequent experiments, 1st-2nd instar larvae were more attracted to the odor of FSK than FS, whereas 3rd-4th instar larvae showed a stronger attraction to FS than FSK. Moreover, 1st-2nd instar larvae were significantly more attracted to FSK extract than FS extract, whereas FS extract attracted significantly more 3rd-4th instar larvae than FSK extract. The specific attraction of 1st-2nd and 3rd-4th instar larvae suggests that each substrate contains stage-specific attractant compounds, supporting the olfactory-mediated host selection of B. impatiens larvae. These findings suggest that FS and FSK volatiles may be useful semiochemicals for monitoring and environmentally friendly management of B. impatiens.

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