Pink bollworm (Lepidoptera: Gelechiidae): large--scale field trials with a high--rate gossyplure formulation

Tests of PBW-ROPE, a hand-applied gossyplure dispenser manufactured by Shin-Etsu Chemical Co., Ltd., Tokyo, Japan, for control of the pink bollworm, Pectinophora gossypiella (Saunders), were conducted on cotton fields in the Imperial Valley, Calif., and in the Mexicali Valley, Mexico. In the Imperial Valley, 23 fields were treated with one of three systems: conventional insecticides (no pheromone), conventional pheromone dispensers (insecticides as needed), or PBW-ROPE pheromone dispensers (insecticides as needed). In the Mexicali Valley, 30 fields were divided between control with conventional insecticide and control with PBW-ROPE dispensers. PBW-ROPE dispensers were applied at the pin-square stage (first flower buds) at a rate of ca. 1,000 dispensers containing 78 g (AI)/ha (release rate of 1.3 g per day per ha at application). Moth populations in all fields were monitored during the season using four Delta traps per field containing 1 mg gossyplure baits. Boll samples were taken weekly or twice weekly from first susceptible boll through September. Significant reductions in insecticide applications of 37 and 42% were obtained in fields in the Imperial Valley treated with PBW-ROPE dispensers compared with fields treated with conventional pheromone dispensers or insecticides, respectively (avg. of 11.4 applications in fields treated with conventional insecticides). Cumulative boll infestations were not significantly different in the three treatments. Trap catches in fields treated with PBW-ROPE dispensers were virtually eliminated through June and July and were reduced 97% in August compared with fields treated with conventional insecticides. The number of insecticide applications in fields in the Mexicali Valley treated with PBW-ROPE were reduced 41% compared with fields treated with conventional insecticides (avg. of 4.9 applications in fields treated with conventional insecticides). Cumulative boll infestations were significantly reduced in August and September in fields treated with PBW-ROPE. Trap catches in August in fields treated with PBW-ROPE were reduced 97% compared with fields treated with conventional insecticides.