Borders Can't Stop Cotton Boll Weevil Migration

Monitoring boll weevil and tracking weevil movements may not be one's idea of having a good time, but this work is surely vital for protecting cotton crops. USDA Agricultural Research Service (ARS) entomologist Tom Sappington has tracked local weevil movements by marking the insects with enamel paint or fluorescent powders and recapturing them later. Now he uses “microsatellites”—short, repetitive DNA sequences—and population assignment tests to find out where weevils came from.

In 2004, a small group of immigrant boll weevils was found next to an eradication zone in Durango, Mexico, where weevils had not been reported for about 10 years. Sappington used weevil microsatellites from this group to study the four other weevil populations from northern Mexico and southern Texas. In this way, the origin of the weevils can be determined. His findings also indicated that final weevil eradication efforts in Texas were being hindered by weevil migration within Texas and the ones from Mexico. Sappington’s work demonstrates that powerful microsatellite markers and population assignment tests are practical tools for monitoring and managing boll weevil pest introductions throughout North America.

Read the news article at http://www.ars.usda.gov/is/pr/2007/070823.htm.