A model for long-distance dispersal of boll weevils (Coleoptera: Curculionidae)

Abstract

The boll weevil, Anthonomus grandis (Boheman), has been a major insect pest of cotton production in the US, accounting for yield losses and control costs on the order of several billion US dollars since the introduction of the pest in 1892. Boll weevil eradication programs have eliminated reproducing populations in nearly 94%, and progressed toward eradication within the remaining 6%, of cotton production areas. However, the ability of weevils to disperse and reinfest eradicated zones threatens to undermine the previous investment toward eradication of this pest. 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 capture 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. A logistic regression model was fit to the probability of capturing at least one weevil in individual pheromone traps relative to specific values of simulated weevil dispersal, which resulted in 60.4% concordance, 21.3% discordance, and 18.3% ties in estimating captures and non-captures. During the first full year of active eradication with widespread insecticide applications in 2006, the dispersal model accurately estimated 71.8%, erroneously estimated 12.5%, and tied 15.7% of capture and non-capture events. Model simulations provide a temporal risk assessment over large areas of weevil reinfestation resulting from dispersal by prevailing winds. Eradication program managers can use the model risk assessment information to effectively schedule and target enhanced trapping, crop scouting, and insecticide applications.

Genetic Profiling to Determine Potential Origins of Boll Weevils (Coleoptera: Curculionidae) Captured in a Texas Eradication Zone: Endemicity, Immigration, or Sabotage?

“…Eradication remains an ongoing project in parts of seven states, but substantial populations remain only in the eastern half of Texas. Boll weevil adults can disperse hundreds of kilometers (Guerra 1988;Spurgeon et al 1997;Sappington 2004a,b, 2006;Westbrook et al 2007), and reintroductions to eradication zones where breeding populations are very low or nonexistent is a chronic concern to growers and eradication authorities because of the expense involved in eradicating new infestations (Culin et al 1990, Allen et al 2004, Westbrook et al 2007, Kiser and Catanach 2008. Surveillance of boll weevils is achieved by systematic networks of traps baited with synthetic aggregation pheromone.…”

Multidisciplinary fingerprints: forensic reconstruction of an insect reinvasion

“…Thus, movement over great distances is wind-aided, and analysis of wind trajectories has been a powerful tool in modelling boll weevil dispersal (Culin et al 1990;Westbrook et al 2000Westbrook et al , 2007. Uncertainties arise in not knowing the precise date of boll weevil arrival in an eradication zone, which can predate capture in a trap.…”

“…In late summer and early autumn, there tend to be more boll weevils flying high above the canopy (Glick 1939;Taft & Jernigan 1964;Rummel et al 1977) where the effect of wind on dispersal is greater than near the surface. Atmospheric dispersion models can help in determining whether wind events were a likely transport mechanism, and if so, to reconstruct the incoming trajectory of immigrants (Westbrook et al 2007). Genetic population assignment analyses based on neutral microsatellite DNA markers have provided important clues to the origin of boll weevils captured unexpectedly in or near eradication zones (Kim et al , 2008.…”

Molecular Diagnostic for Boll Weevil (Coleoptera: Curculionidae) Based on Amplification of Three Species-Specific Microsatellites

“…The ability of boll weevil adults to disperse hundreds of kilometers is well-documented (Guerra 1988;Spurgeon et al 1997;Sappington 2004a,b, 2006;Westbrook et al 2007), and both natural dispersal by ßight (Culin et al 1990, Westbrook et al 2007) and human-mediated transport (Sappington et al 2004Kim et al 2008) can reintroduce boll weevils to an eradication zone. The threat of reintroduction is a constant concern because of the expense involved in eliminating a colonizing population that successfully establishes , Westbrook et al 2007, Kiser and Catanach 2008.…”

“…The threat of reintroduction is a constant concern because of the expense involved in eliminating a colonizing population that successfully establishes , Westbrook et al 2007, Kiser and Catanach 2008. A population genetics approach using neutral molecular DNA markers has provided important clues to the origin of boll weevils captured unexpectedly in or near eradication zones (Kim et al , 2008.…”