Postemergence Billbug Control in Field Corn, 1979

Seed planted by farmer on April 3 in Delway, Sampson County, North Carolina. Four granular insecticides were tested to determine their potential for controlling the southern corn billbug as a postemergence application in a sandy loam soil. Counter 15G, Counter Coated 15G, Lorsban 15G and Temik 15G were applied at 2 pounds ai/acre with a gravity flow granular applicator in a 7-inch band over the plants on April 20, 3 days after attack was initiated. Cultivation was simulated with a 3 hoursepower garden Rototiller at application. Test design was a randomized block with 6 row plots 50 ft × 36 inch rows × 5 ft alleys and 4 replicates. All plots were rated for damaged plants, plant population and yield. Plant populations at treatment averaged 1 plant per 1.1 row ft in both infested and noninfested areas of the field. The poor stand was later attributed to poor planter adjustment. On May 15 another stand count was made and plants rated for injury on a scale of 0-3: 0 - no visual evidence of injury; 1 - superficial feeding; 2 - damage to terminal leaves moderate to heavy; 3- terminal shoot dead and/or plant suckering. Counter 15G (both formulations) and Lorsban 15G plots contained more undamaged and less severely damaged plants plus a greater stand count than Temik 15G or check plots. Yields taken by hand September 19 were generally low, but this can be attributed to the poor initial stand. All data was derived from 100 ft of row per plot. Significant differences existed at the .05 level with respect to damage rating and yield.