An Arrestant and Feeding Stimulant for the Boll Weevil in Water Extracts of Cotton-Plant Parts1

Abstract

A powerful arrestant and feeding stimulant for boll weevils (Anthonomus grandis Boheman) was found to exist in water extracts or all cotton-plant parts and square components investigated. A biological assay method was developed by utilizing agar plugs impregnated with the extract and wrapped with filter paper, to determine quantitatively the concentration of the arrestant. All the cotton plant parts investigated were found to contain the arrestant in sufficient concentration for bioassay. Flowers at the stage or anthesis and whole squares contained the highest. In the square, the exterior component (calyx) contained the highest but the amount progressively decreased interiorly, with the lowest in the ovary. Presence of the arrestant and feeding stimulant in germinated seed or seedlings indicated they could be used as screening agents in host-plant resistance programs, obviating need for fruiting plants. Correlation between weevil feeding response and concentration was almost direct, with the bottom limit at 10,000 p.p.m. Agar plugs with small amounts of water extract from squares elicited a much higher feeding response than a commonly used artificial adult-weevil diet.