Alfalfa Weevil Control, 1992

The plots, 34 ft × 34 ft, were in a 3-yr-old stand of ‘Cimarron’ variety alfalfa. All treatments and the untreated control were replicated 3 times in a completely randomized design. Sprays were mixed to apply the proper rates in 20 gal total vol/acre. Treatments were applied on 23 Apr with a low pressure, low volume, Hahn field sprayer equipped with 21 Spraying Systems 8003 stainless steel Tee Jet nozzles and operated at a pressure of 35 psi. Valent W-77 non-ionic spreader activator (0.25 % volume/volume) was added to an Ambush 2 EC treatment at 0.2 lb (AI)/acre. A standard treatment of Furadan 4 F was applied at the rate of 0.5 lb (AI)/acre for comparison. Population densities of AW larvae were determined 5, 8, 11, 18 and 21 DAT by collecting 10 sweeps from each plot with a standard 15-inch-diam beating net. A phytotoxicity rating was made 5 and 8 DAT in the Lorsban plots where 1 = no damage and 9 = complete kill with 2 through 8 being intermediate.