Laboratory Evaluation of Tarnished Plant Bug Tolerance to Insecticides, 1995

Formulated insecticides were evaluated for toxicity in the laboratory to TPB collected from wild host plants surrounding cotton near Stoneville, MS. Populations were collected on 2 May, 15 Jun, 27 Jul, and 12 Sep, and placed in a cage in the laboratory for 24 h. Treatments were applied for each population immediately after the 24 h holding period. Bioassays were conducted by applying insecticides to cotton terminals (‘DES 119’) held in floral piks in water using a laboratory spray chamber. The spray chamber was calibrated to deliver 6 gal/acre at 2 mph with 30 psi through one TX6 nozzle. Each treatment consisted of 3 replicates of 10 terminals/replicate. The checks were treated with water only. Two adult TPB were placed on each terminal 30 min after spraying and held in ventilated cups (10 oz) at 85°F and 55-60% RH. Mortality was determined at 48 h after placement in the cups. TPB not moving when prodded were considered dead. Mortality in water checks was never greater than 10%; data were corrected for check mortality using Abbott’s formula. Data were arcsin transformed for analysis; actual percent mortalities are shown.