Laboratory Screening for Control of Alfalfa Looper, Winter 1976-77

Laboratory screening for control of larvae of the alfalfa looper was conducted by dipping bouquets of the foliage of 5 greenhouse-grown 30- to 40-day-old ‘Perfected Freezer’ pea seedlings in 1-liter solutions of the insecticides, swirling the foliage until it was thoroughly wetted and then infesting the treated foliage with larvae. The solutions were prepared by dissolving the insecticide in 20 ml of acetone and mixing that with 1 liter of tap water to which 5 drops of wetting agent were added. Additional dilutions were prepared by decanting 500 ml of the original solution and mixing it with 500 ml of tap water to which 3 drops of wetting agent were added. Excess solution was shaken from the foliage which was then air dried for 2 hours. The dry, treated bouquets were placed individually into 2-liter polyethylene canisters that were closed with cheesecloth after the bouquets were infestedwith the test insects. Each of the 3 replicates of each treatment was infested with five, second-to third- and five fourth- to fifth-stage larvae from the laboratory culture. The efficacy of each treatment was determined by examining the foliage for feeding damage and the larvae for mortality every 24 hours after infestation until mortality was complete or had stabilized (usually in 3 to 4 days). The test was conducted in the greenhouse at 20°C with a 16-hour photophase (partially augmented by artificial lighting).