Evaluation of Insecticides for Suppression of Sorghum Midge on Sorghum,1996

Abstract

Abstract Selected insecticides were evaluated for sorghum midge control at the Texas Agricultural Experiment Station Research Farm near College Station, TX. Seed of hybrid sorghum (AT X 399 x RT X 430) was planted 29 May on rows spaced 30 in. apart. Insecticide treatments were compared in plots, 6 rows X 40 ft long, arranged in a RCB design with 4 replications. Insecticides were applied to the middle 2 rows of plots. Insecticides were applied between 0800 and 0900 h CDT by using a hand-held backpack sprayer with TX-3 hollow cone nozzles at 35 psi, producing a finished spray volume of 4.9 gpa. Insecticides first were applied 23 Jul when 10-50% of the panicles were flowering; insecticides then were applied 26 Jul when 90-100% of the panicles were flowering. Adult sorghum midge abundance was assessed just prior to each application by counting the number of sorghum midges enclosed in clear plastic bags on 10 individual sorghum pan-icles. The panicles were cut from the plant and returned to the laboratory for examination and sorghum midge counts. Grain yield data were collected from the 2 middle rows per plot. Panicles were hand harvested from 2 selected 8.75-ft sections of row/plot and mechanically threshed. Data were statistically analyzed by using ANOVA and LSD.