Malathion for Control of Black Grass Bug, 1978

Abstract

Abstract Malathion ULV concentrate was applied at 8, 6 and 3 fluid oz of technical material (91%)/acre to 40 acre plots replicated 4 times, and 2 fluid oz of technical material/acre was applied to a 100 acre plot near Llaves, NM from May 10 through 13, 1978. All plots had been reseeded with Crested Wheatgrass. All dosages except the 8 oz treatment were diluted with water (to emulsify the malathion Triton X - 190 was used at 20% of the volume of malathion). Six And 3 oz treatments were applied in 8 oz of fluid/acre while the oz treatment was applied in 16 oz of fluid/acre. All treatments were applied with a Cessna Ag-truck 188B aircraft at 40 psi through a standard Cessna hydraulic driver spray system. Eleven 8001 flat fan nozzles were used for the 8, 6 and 3 oz treatments and (15) 80015 flat fan nozzles were used for the 2 oz treatment. All nozzles were rotated 90° to the slip stream. Flight speed was 120 mph; flight height and swath width were 30 and 75 ft respectively. Malathion ULV concentrate was applied at 3 oz of technical malathion, 2% Triton X-190, and water in 8 oz of fluid/acre to 3000 acres of reseeded Crested Wheargrass ca 15 miles NE of McNary, Arizona on May 18, 1978. This treatment was applied with a Turbo Thrush aircraft at 40 psi using 8008 nozzles. Application speed was 140-150 mph; flight height and swath width were 50 ft and 100 ft, respectively. Results on 40 acre plots were assessed by counting live black grass bugs in 4 subsamples (5 sucks/subsample) per plot taken with a 1/2 foot diameter modified de-vac. Results on 100 acre and 3000 acre plots were assessed by counting live black grass bugs at 30 sample sites (5 sucks/site) within each plot. Samples were taken 1-2 days prior to treatment and 2 days and 7 days following treatment. Both species listed above were found in the New Mexico plots, only L.hesperius was present in the Arizona plot.