Section 18 Approval Granted For Rice Water Weevil Control

PORTAGEVILLE, MO.
   Good news for farmers with continuing infestations of rice water weevil. Der-macor TM X-100 (DuPont) will be available for the 2008 growing season for rice water weevil control, thanks to a Section 18 recently granted by the Environmental Protection Agency. Dermacor will be available for all the mid-South rice growing states.
   Dermacor may be applied to dry rice seed for drilled or broadcast seeding. It is not currently available for water seeded rice systems. The overall acreage will be limited due to product availability and acreage allotted within each state varies. Application rates vary based on the seeding rate.
   Dermacor has been evaluated for efficacy against the rice water weevil for three years in Texas and Louisiana and in one year in Missouri, Miss-issippi and Arkansas. Control with the high rates of Dermacor was better than a single application of Karate ®. All insecticide treatments increased yields over the non-treated ch-eck. The greatest increase was found with Dermacor. Prior experience suggests Dermacor will be as effective or better than Icon at controlling rice water weevil in farmer fields.
   Greenhouse experiments conducted in Louisiana suggest that Dermacor reduces rice water weevil in treated plants primarily by killing small larvae soon after eggs hatch. This means, that even though the plants are protected from larvae, adults will still feed and scar leaves. Rice water weevil control is expected to be enhanced with Dermacor over current control options because there are no timing issues associated with seed treatments like there can be with foliar applications. Also seed treatments generally result in less damage to young plants because the delivery of the insecticide to the pest is more efficient and the seed itself is protected.
   Dermacor has the potential to partially control other early season pests. Data obtained in greenhouse studies in Louisiana showed that Dermacor-treated rice plants (three to four leaf stage) caused 100 percent mortality of fall armyworm larvae. Researchers are hopeful that Dermacor will prevent stand losses from the grape colaspis; however, currently there is no data to support this statement. Data from Texas have also shown promise in reducing stem borer damage. Δ
   Dr. Kelly Tindall is an Entomologist with the University of Missouri Delta Center at Portageville.