Insecticidal Control of Sorghum Webworm in Louisiana, 1985

Six insecticides were evaluated for control of the sorghum webworm at the LSU, Idlewild Experiment Station, East Feliciana Parish, LA. Grain sorghum was planted in a conventional manner on 25 May. Insecticide treatments were 50 ft × 1 row with an untreated row between treatments. A completely randomized block design was used with 4 replications, 5 ft alleys between replicates and 38 inch row spacing. Insecticides were applied using a backpack CO2 pressurized sprayer delivering 16 gal/acre at 55 psi through a single Teejet 8002 E nozzle. Sprays were applied approximately 6 inches above the sorghum heads on 6 Aug. The effectiveness of the treatments was evaluated on 9 Aug by counting the number of live webworms on 5 randomly selected sorghum heads from each treatment in each replication. Webworms were counted by clipping and bagging the heads, shaking them over a white porcelain pan, and counting the number of live webworm larvae.