Alfalfa Weevil Control, 1982

Experimental insecticides were applied to an established alfalfa field at the Middle Tennessee Experiment Station, Spring Hill, TN on Mar 31. Furadan and Imidan were included as standards. Treatments, replicated 4 times in a randomized complete block design, were applied to plots 18 ft x 20 ft at the rate of 25 gal/acre at 30 psi with a CO2-powered boom sprayer mounted on bicycle wheels. Five pendulum sweeps were taken with a 15-in diameter insect net in each plot at 6 and 14 days. There was a mean of 214 alfalfa weevil larvae before treatment. Rainfall was 0.92 in within 24 h prior to treatment and 0.16 within 4 h after treatment. Weather conditions for the 14-day period after treatment were: Average maximum (61.9°F) and minimum (36.4°F) temperature and total rainfall of 1.39 in. There was 100% tip damage and the field had a frosted appearance prior to treatment. Because of uneven stand, no yields were taken.