Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 27, 2002
Publication Date: June 1, 2003
Citation: Showler, A. 2003. Effects of routine late-season field operations on numbers of boll weevils (Coleoptera: Curculionidae) captured in large-capacity pheromone traps. Journal of Economic Entomology. 96(3):680-689. Interpretive Summary: A large capacity boll weevil trap captured more boll weevils than the conventional Hercon TM trap, and it was useful for measuring large boll weevil populations during the late season in the Lower Rio Grande Valley of Texas. Numbers of adult boll weevils caught following defoliation, harvest, shredding, and stalk-pulling showed that populations of boll weevils persist in cotton fields after the crop has been destroyed. Deployment of multiple boards in cotton fields during the late season suggested that boll weevil populations might be affected by large capacity trapping.
Technical Abstract: Flat and cylindrical adhesive boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), pheromone traps captured more (P less than or equal to 0.05) boll weevils than the Hercon TM trap during the late cotton growing season; a flat plywood board collected the most boll weevils. The board trap, used for measuring large late season adult boll weevil populations in the Lower Rio Grande Valley of Texas, 2000 and 2001, collected more (P less than or equal to 0.05) weevils when deployed close to natural and cultivated perennial vegetation, and mean numbers of captured weevils were greater (P less than or equal to 0.0001) on the leeward than on the windward sides of the board traps. The board trap had an estimated capacity of approximately 27,800 boll weevils, and that capacity allowed for better measurements of large adult boll weevil populations than the Hercon trap. Measurement of adult boll weevil numbers following routine field operations (defoliation, harvest, shredding, and stalk-pulling) demonstrated that large populations of boll weevils persist in cotton fields after the cotton crop has been destroyed. Significant (P less than or equal to 0.05) increases in the percentage variation of trapped boll weevils relative to the numbers collected just before each field operation were observed after each different operation, and the percentage variations followed a quadratic pattern with significant correlation (P < 0.0001; 0.59 < adj-r**2 < 0.73). Numbers of adult boll weevils captured on board traps deployed at approximately 15-m intervals on edges of cotton fields suggested that boll weevil populations in flight after field disturbances might have been affected by the large capacity traps.