Lesser Cornstalk Borer Control in Sorghum in North Florida, 1986

Sorghum was planted 16 Jul at a seeding rate of ca. 7 lb/acre in Jackson Co. Experimental design was an RCB with 4 replicates. Plot size was four rows by 100 ft. Standard practices were followed for sorghum production and weed and disease control. Treatments made at planting were applied with a tractor mounted applicator equipped with an electronic metering device set to deliver granules immediately in front of the press wheel. Spray treatments were applied in 25 gal/acre of spray at the 3-4 leaf stage (29 Jul) with a CO2-powered backpack sprayer equipped with three nozzles/row and set at 36 psi. Beauveria bassiana (Abbott Laboratories, RS-252, 1 × 1010 coni-dia/g) was applied in a 0.01% Tween 20 solution. All other spray materials were applied in water alone. Efficacy data were taken 25-26 Aug, at the 8-10 leaf stage. Stand density was determined by counting the number of live plants in three 1-m by 1-row samples/plot. LCB damage and density were evaluated by uprooting and visually inspecting all plants in each 1-m sample for larvae or characteristic damage symptoms. Yield data were taken 29-30 Oct by harvesting two 2-row by 8-ft samples/plot.