Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/10/2003
Publication Date: 4/1/2004
Citation: Greenberg, S.M., Sappington, T.W., Setamou, M., Coleman, R.J. 2004. Influence of different cotton fruit sizes on oviposition and survival to adulthood of the boll weevil (Coleoptera: Curculionidae). Environmental Entomology. 33(2):443-449. Interpretive Summary: The boll weevil is a primary insect pest of cotton for which the National Cotton Council estimates annual crop losses and control costs of $300 million in the U.S. Control of this insect is critical to cotton production, but use of broad-spectrum insecticides can lead to environmental problems and insecticide resistance. Better knowledge of the biological relationships between boll weevils and cotton plants is required to develop environmentally-safe and efficient strategies for controlling boll weevils. In this study, the size of cotton fruit significantly affected egg laying and feeding by adult female boll weevils. Boll weevils laid a maximum number of eggs in fruit of 5-8 mm diameter, and survival to adulthood was highest on fruit of 7-10 mm diameter. Boll weevils fed most frequently on fruit of 9-10 mm diameter. These findings will improve our capability to develop methods that predict fruit losses and changes in field populations of boll weevils.
Technical Abstract: Boll weevil, Anthonomus grandis grandis Boheman, feeding and oviposition punctures, and survival to adulthood were determined on 10 different cotton fruit sizes: squares with a diameter of 1.5-2.0 mm ("pinhead"), 3.0-3.5 mm ("matchhead"), 5-6 mm, 7-8 mm, 9-10 mm; candle; bolls with a diameter of 10-15 mm, 15-20 mm, 20-30 mm, and >30 mm. Oviposition and feeding punctures were significantly affected by cotton fruit size. The fewest eggs were oviposited in boll sizes >30 mm. Females did not oviposit in "pinhead" squares. The highest number of eggs were recorded in square sizes of 5-6 mm and 7-8 mm. Boll weevil survival to adulthood was highest on square sizes of 7-8 mm or 9-10 mm (58.6 - 59.7%), and they did not survive on "matchhead" squares, and boll size >30 mm. Duration of development was longest on boll sizes of 15-20 and 20-30 mm (18.2-18.8 days). The growth index (percentage immature survival divided by immature development time of boll weevil females was 2.8-fold higher when they developed on square sizes of 7-8 mm or 9-10 mm than on a boll size of 20-30 mm.