Improved Feeding Bioassay for the Boll Weevil (Coleoptera: Curculionidae)1

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Abstract
An improved feeding bioassay was developed to assess effects of semiochemicals on feeding by adult boll weevils, Anthonomus grandis grandis Boheman. The bioassay eliminates reliance on cotton squares or preparation of paper-wrapped feeding plugs common to previous methods. Any solvent may be used to deliver semiochemicals without observable adverse effects on the insect’s feeding. A series of experiments was conducted to select a preferred media and its surface shape, number of feeding sites (wells) and insects per bioassay dish, and light conditions. The reliability of the method was determined by comparing results generated from it with those from a dipped cotton square assay. Methanolic solutions of quercitrin, rutin, and crude cotton tannin were coated onto cotton squares and also applied to the lens papers in the plate bioassay. Quercitrin was a feeding deterrent in both bioassays while rutin was a feeding stimulant in the plate bioassay. Tannin was neither stimulatory nor deterrent compared with controls in either bioassay.