In the present study we tested the effect of peanut, Arachis hypogaea L. (Leguminoseae), stem infection by the white mold fungus, Sclerotium rolfsii Saccodes (Basidiomycetes), on the oviposition preference of beet armyworms, Spodoptera exigua Hübner (Lepidoptera:Noctuidae). Additionally, we tested the effect of peanut white mold infection on the foraging ability of the BAW larval parasitoid Cotesia marginiventris. We found that adult beet armyworms (BAW) oviposited more on peanut plants that were infected by the white mold fungus. Further experiments revealed that BAW oviposition preference was mediated by volatile emissions and also by internal biochemical changes induced in the plants by the fungal infection. The parasitoid C. marginiventris landed more frequently on infected than on healthy peanut damaged by BAW. The parasitoids were also more responsive to volatiles emitted by fungus-infected peanut plants than their healthy counterparts when plants were exposed to feeding by BAW larvae.
Species 1: Lepidoptera Noctuidae Spodoptera exigua (Beet armyworm)
Species 2: Hymenoptera Braconidae Cotesia marginiventris
Keywords: tri-trophic interactions, fungal infection
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