Feeding and oviposition preferences of sweet potato weevil,Cylas formicarius elegantulus (Summers), on storage roots of sweet potato cultivars with differing surface chemistries.

Cores from sweet potato [Ipomoea batatas (L.) Lam.] storage roots (Centennial, Jewel, Resisto, and Regal cultivars) were presented to sweet potato weevils [Cylas formicarius elegantulus (Summers) (Coleoptera; Curculionidae)] in multiple-choice, limited-choice, and no-choice bioassays. Centennial, a susceptible cultivar in field-plot experiments, was preferred for feeding and oviposition by female weevils in choice bioassays, and for ovi-position in no-choice bioassays, compared to three other cultivars. Analysis of root surface chemistry showed a tentatively identified triterpenol acetate in Centennial, which was not found in the more resistant cultivars; another root surface component was found in higher concentrations in the more resistant cultivars.