Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/2004
Publication Date: 8/1/2004
Citation: Sappington, T.W., Brashears, A.D., Parajulee, M.N., Carroll, S.C., Arnold, M.D., Baker, R.V. 2004. Boll weevil (Coleoptera: Curculionidae) survival through the seed cotton cleaning process in the cotton gin. Journal of Economic Entomology. 97(4):1323-1329. Interpretive Summary: The boll weevil is a major pest of cotton, and great efforts are underway to eradicate it from the U.S. There is concern that weevils that are transported inside modules of harvested cotton from neighboring infested areas to cotton gins may escape and reinfest a weevil-free area. We found no evidence that weevils can survive the machinery in the cotton gin that cleans and drys the seed cotton in preparation for removal of the seed from the cotton lint, even when the dryers are not turned on. Weevil survival in the dryers is also low at moderate to high temperatures, especially when two dryers are run. However, we did find a small number of live weevils in the green boll or rock trap, and this may represent the greatest threat of boll weevil escape at the gin. These results will help state and federal agencies draft regulations for ginning weevil infested cotton in eradication zones.
Technical Abstract: There is concern that gins located in boll weevil (Anthonomus grandis Bohemon) eradication zones may become points of reintroduction when they serve customers in a neighboring infested area. Previous work showed that transport of live weevils to the gin within cotton modules is common. We tested boll weevil survival through two typical machine sequences used in commercial cotton gins to clean and dry the seed cotton in advance of the gin stand, as well as through two inclined cylinder cleaners, and one or two tower dryers operated at different temperatures. Large numbers of laboratory-reared boll weevils were marked with fluorescent powder, fed into the test system, and recovered under black lights. We found no evidence of survival through the seed cotton cleaning systems or through the two inclined cleaners alone, even when the dryers were not heated. 95% upper confidence limits were calculated for the observed zero recoveries based on sample size and the binomial distribution, and these represent the statistical worst-case survival potential. Survival through heated tower dryers declined rapidly to zero at higher temperatures, especially when two dryers were running. Although we conclude that the potential for survival of weevils in the seed cotton to the gin stand is zero or close to zero, a small percentage of live weevils were recovered in the green boll/rock trap, which may represent the greatest threat of reintroduction at the gin. Escape of live weevils with the gin trash is also possible, and studies addressing this issue will be presented elsewhere.