Comparison of Acephate Formulations for Control of Adult Grasshoppers on Rangeland, 1983

Each of two 640-acre adjacent square blocks of 5th stage to adult grasshopper economically-infested mixed-grass rangeland 14 miles northeast of San Carlos, Ariz., was used for the test. The population was intentionally allowed to develop to an advanced age structure to achieve a more severe test of the formulations since younger grasshoppers generally require less insecticide for control. Normal control programs would usually be conducted on a younger age structure. Each block was aerially sprayed with either the Orthene Tree and Ornamental Spray or Orthene Speciality Concentrate formulation of acephate at 0.094 lb (AI)/acre in a total volume of 32 oz/acre on 11 to 13 July 1983. Both treatments were diluted with water and contained Grandma’s Onsulfured Molasses (added for feeding enhancement) and Nalcoetrol (an anti-evaporate, anti-drift additive) at the respective rates of 3% by volume and 9 oz/100 gal of mix. Both treatments were applied from an Cessna Ag Truck aircraft operating at 120 mph. Twelve 804 flat fan stainless steel Tee Jet nozzle tips directed 45° down and aft were used to apply the treatments at an altitude of 50 ft and 38 lb/in2 . A working swath width of 75 ft was used.