Pecan farmers are closely monitoring and protecting their crop these days as the nuts are pushing toward final maturity. The bug getting the most attention right now is the Pecan Weevil. This insect is a larger version of its infamous kissing cousin the Boll Weevil. From August through September is when weevils start their annual emergence from the orchard floor to attack pecans.
This summer, some Dougherty County 4-H'ers decided to help farmers by building Pecan Weevil monitoring traps. Farmers bought these traps from the 4-H Club and mounted them on trees where weevils have been a problem in the past. Once or twice a week, the traps are checked for newly emerged weevils to see if a pesticide application is necessary. Ideally, this detection system helps farmers use less pesticide and when spraying does become necessary it will be more timely and effective.
The Pecan Weevil is considered the most damaging of all insects infesting Georgia pecans. University of Georgia entomologists measure economic impact in terms of money spent on insect control and income lost from their damage. Statewide this one pest can pick pecan producer's pockets for over $9 million. No wonder they are serious about finding and stopping Pecan Weevils.
Adult weevils emerge from the soil starting in early August, but the migration can last well into September. Many times farmers notice increased emergence after a heavy rain softens the soil. Before pecan shells harden, punctures from feeding cause the nuts to drop prematurely. More significant damage occurs when mated females start laying eggs inside the immature pecan kernel.
Other than hurricane force winds, weevil egg laying damage is the last major hurdle farmers may face before harvesting their crop. The eggs hatch into grubs and feed inside the protected kernel for about 30 days before leaving behind a worthless nut.
Many people have found the small circular exit holes left on pecan shells by the mature grub. Next, they burrow into the ground and remain in the larval stage for one to two years before pupating into an adult Pecan Weevil.
The adult remains in the soil until the following August, when the whole process starts over again. As the adult weevils emerge, they walk or fly to a pecan tree to start feeding. Information from Texas A&M shows that 77 percent of emerging adults fly to and light on a nearby tree trunk at a height of 6- 8 feet. That's where the 4-H traps are standing guard. Like a vertical fish trap, they catch the weevils as they walk upward toward the tree canopy for their annual party.
Dougherty 4-H'ers made over 80 traps this summer to help protect America's favorite nut crop. Proceeds from the project helped send two 4-H'ers to summer camp. This program is just one example of how today's farmers are using Pest Management tools to be more selective and efficient in their pesticide use. The University of Georgia has developed other detection methods for Pecan pests. Every other spring they offer training in Tifton at the "Pecan Scout School." For more information contact your local county agent.
Rad Yager, UGA County Extension Agent for Dougherty County can be reached at (229) 436-7216