Browsing Cotton Report 1987 by Authors
A New Egg Sampling Plan for Pink Bollworm Reduced Insecticide Use by 35 PercentHutchinson, Bill; Beasley, Bud; Henneberry, Tom; Martin, Jeanette; Western Cotton Research Laboratory; Cooperative Extension, University of California (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)During the past two years we developed an egg sampling plan for the pink bollworm (PBW) to provide a more accurate index of moth (target stage) activity than conventional larval sampling. The plan requires that only the presence or absence of eggs laid on bolls be determined to decide when insecticide treatments are needed. Our objective in 1986 was to determine whether egg sampling vs. conventional treatment criteria (e.g., larval infestations, trap catches of male moths, and /or fixed -spray intervals) provided more optimal timing of insecticide applications in a 640-ac field test. Implementation of the egg sampling method in 8 of the 16 fields resulted in an average 35 percent seasonal reduction in insecticide use when compared to conventional methods. Despite the reduction in insecticide use, PBW larval infestations were not significantly different (P = 0.45) in fields samples for eggs vs. fields sampled for larvae from June to September. Yields were also not significantly different (P = 0.40) between the two sets of fields.