The efficacy of sex‐attractant monitoring for the pea moth, Cydia nigricana, in England, 1980–1985

Abstract

SUMMARYThe efficacy of monitoring the pea moth (Cydia nigricana) in dry‐harvested pea fields with pheromone traps was evaluated on commercial farms in Eastern England used by ADAS as back‐up monitoring sites. In particular the use of a ‘threshold’ catch to determine both the need for and timing of insecticide sprays was evaluated. Fields in which ‘threshold’ catches were achieved had more damage in unsprayed plots than fields in which there were no ‘threshold’ catches. When two sprays were applied to crops at ‘threshold’ sites, the timing of the first predicted by the monitoring system, excellent control was achieved with 85% of crops having less than 1% peas damaged, and none more than 2–3%. Incorrectly timed sprays, or even one correctly timed spray, produced erratic control.Simple assessments of economic loss show that it is unnecessary to spray crops in which a ‘threshold’ is not achieved. Spraying ‘threshold’ crops, however, is very worthwhile and applying two sprays, the first timed with pheromone traps, will be particularly advantageous to both growers of peas for human consumption when ‘clean’ crops are at a premium, and to seed producers.The data can be used to predict the probabilities of damage levels, assuming different control strategies.