Suppression of Sunflower Moth on Sunflower with Selected Insecticides, 1987

Sunwheat' sunflower was planted 20 May at the Southwest Kansas Experiment Station, Garden City, in a furrow-irrigated field. Seven insecticidal treatments and 1 untreated check were replicated 4 times in a randomized complete block design. Individual plots were 4 rows (3 m) × 12 m with 1.52 m separating blocks. Plots were irrigated and cultivated as needed. Insecticides were applied with a CO2-pressurized backpack sprayer using 106.6 liters of finished material/ha at an operating pressure at 2.1 kg/cm2. All treatments were applied on 22 Jul (50% bloom) and again on 27 Jul (100% bloom). The initial treatment was scheduled for 20% bloom, but poor weather conditions prevented this. Only the 2 middle rows of each plot were sprayed to minimize plot-to-plot contamination from drift. Temperatures at the start of application (early morning) were 17.2°C and 18.3°C on 22 and 27 Jul, respectively. Larval densities were determined by dissecting and examining 5 heads randomly selected from each plot. Heads were sampled 2 wk after the first insecticide application. Total rainfall from 1st application to posttreatment evaluation was 3.35 cm. Plots were not harvested for seed yield because severe bird depredation and head rot negated any differences that might have occurred as a result of insecticidal treatments.