ARS | Publication request: A Model Evaluation of Long-Distance Dispersal of Boll Weevils

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: January 18, 2007
Publication Date: June 28, 2007
Citation: Westbrook, J.K., Eyster, R.S., Allen, C.T. 2007. A model evaluation of long-distance dispersal of boll weevils. In: Proceedings of the Beltwide Cotton Conferences, January 9-12, 2007, New Orleans, Louisiana. p. 337-344.

Interpretive Summary: Boll weevil eradication programs are conducted within individual cotton production zones that share similar production schedules. Although these programs progress toward eradication within each zone, concerns remain about the possibility of weevil dispersal between eradication zones. In this study, an atmospheric dispersion model was used to simulate daily wind-aided dispersal of weevils from the Lower Rio Grande Valley (LRGV) of southern Texas and northeastern Mexico. Simulated weevil dispersal was compared with weekly captures of weevils in traps around the perimeter of cotton fields along highway trap lines between the LRGV and the South Texas / Winter Garden zone of the Texas Boll Weevil Eradication Program. A logistic regression model was developed to estimate the probability of capturing at least one weevil in individual traps relative to specific values of estimated weevil dispersal. Model simulations provide a risk assessment of weevil re-infestation from dispersal by prevailing winds, information that program managers can use to appropriately schedule and target enhanced trapping, crop scouting, and insecticide applications.

Technical Abstract: Boll weevil eradication programs have progressed toward eradication within each zone, but concerns remain about the possibility of weevil dispersal between eradication zones. In this study, the HYSPLIT atmospheric dispersion model was used to simulate daily wind-aided dispersal of weevils from the Lower Rio Grande Valley (LRGV) of southern Texas and northeastern Mexico. Simulated weevil dispersal was compared with weekly captures of weevils in pheromone traps along highway trap lines between the LRGV and the South Texas / Winter Garden zone of the Texas Boll Weevil Eradication Program. The probability of capturing at least one weevil in individual pheromone traps relative to specific values of simulated weevil dispersal was fitted by a logistic regression model, which resulted in 60.4% concordance, 21.3% discordance, and 18.3% ties in estimating captures and non-captures. Model simulations provide a risk assessment of weevil re-infestation from dispersal by prevailing winds, information which program managers can use to appropriately schedule and target enhanced trapping, crop scouting, and insecticide applications.