IDENTIFYING THE PREDATORS THAT INTERFERE WITH BOLL WEEVIL TRAPPING AND EVALUATING LURE/INSECTICIDE COMBINATIONS

Authors: Armstrong, John; RICHMAN, DAVID - NEW MEXICO STATE UNIV

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/5/2006
Publication Date: 5/1/2006
Citation: Armstrong, J.S., Richman, D.B. 2006. Identifying the predators that interfere with boll weevil trapping and evaluating lure/insecticide combinations. In: Proceedings of the Beltwide Cotton Conferences, January 3-6, 2006, San Antonio, Texas. 2006 CDROM.

Interpretive Summary: A program was initiated in the fall of 2005 to eradicate the boll weevil from South Texas, one of the last U.S. cotton production areas for which a new Eradication Program was needed. Eradication programs have successfully relied on pheromone traps for detecting weevils, but improvements in the trapping system are necessary to ensure detectability when weevil populations are low or when there are re-infestations in eradicated areas. We evaluated the use of a modified boll weevil trap with the intention of preventing arthropods from interfering with trap efficiency; identified the arthropods that interfere with trap efficiency; and evaluated dispensers that contained the weevil attractant (grandlure) and an insecticide (dichlorovos) in the same or separate dispensers. The trap modification did not reduce the number of unwanted arthropods, primarily spiders, that interfered with trap captures of weevils. Spiders interfered with trapping by preying directly on the captured weevils and by webbing the entrance to the trap. The combined dispenser with grandlure and dichlorovos was just as effective in trapping and killing weevils as were the two compounds on separate dispensers. The results of this study will help to ensure efficacy of trapping and detection of boll weevils as the Eradication Program advances to eliminate this major cotton pest from the U.S.

Technical Abstract: A modified boll weevil trap was evaluated to determine if it would reduce the number of unwanted predators that interfere with trapping efficiency. Arthropods responsible for interfering with boll weevil trap captures were surveyed from both trap types. A separate study was conducted to evaluate boll weevil trap efficiency when grandlure was combined with an insecticide (Combo Lure®) dispenser versus the insecticide (DDVP) and grandlure in separate dispensers. The modified trap did not reduce the unwanted arthropods. Ninety eight percent of the arthropods came from 13 different spider families representing fourteen known species, and fifteen were identified to genus. The spider families most commonly collected from boll weevil traps were Anyphaenidae, Araneidae, Lycosidae, and Tetragnathidae. The combination lure-insecticide (Combo Lure®) attracted boll weevils as well as the lure and insecticide presented in separate dispensers. These two treatments were not significantly different from one another in causing mortality to captured weevils and other arthropods caught in the trap, and both caused significantly more mortality of weevils than a grandlure dispenser in the absence of the insecticide dichlorovos.