Date: 3/30/99

Time: 3:50

Type: Symposium

Number: 156

Current status and future of Mexican corn rootworm areawide management in Texas

J.R. Coppedge, W.C. Hoffmann and I.W. Kirk, USDA-ARS, College Station, TX 14853
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In 1998, USDA-ARS continued its effort on the areawide management of corn rootworm. In Bell County, TX (near Temple, TX), where the pilot study was in its third year, only 80 acres out of 2,700 acres of corn and milo reached treatment threshold and was treated. Local producers requested adding 1,800 acres into the management area, all which required adult control treatments. Additional pilot studies were initiated near Wharton (1,800 acres), Hondo (1,200 acres), and Dalhart (3.050 acres), TX. Approximately 600 acres in the Wharton area required treatment. These were all fields where corn was planted after corn. The insecticide application resulted in a >95% reduction in Mexican corn rootworm (MCR) adults. At Hondo, good initial kill of MCR adults was obtained; however, there was some population increases about two weeks after treatment. These increases likely occurred when MCR adults began to migrate from untreated dryland corn, which had been abandoned because of drought stress. At Dalhart, initial treatments effectively reduced Western corn rootworm adults; however, later treatments to two 500-acre pivots only reduced the adult population < 50%. This may have been the result of the aerial applicator failing to follow proper application procedures. Additionally, the study fields may have received rain showers immediately after the treatment. Data compiled after the corn harvest revealed that there was significantly less aflatoxin in the corn from the management area compared with corn outside the management area in Bell County. The Wharton pilot study data showed that there was a positive correlation between adult MCR trapped and the level of aflatoxin detected in the corn samples. Fields in Wharton with the lowest beetle captures also had the highest yields.

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