Relationship between Euschistus conspersus (Hem., Pentatomidae) pheromone trap catch and canopy samples in processing tomatoes

This study identified statistically significant, and practically important, seasonal pheromone trap response dynamics of Euschistus conspersus (Uhler) in processing tomatoes in 12 fields over 5 years in California, USA. Commercial fields were monitored weekly using traps baited with Euschistus spp. pheromone and direct canopy shake samples. Regression analysis determined no significant relationship between the two sampling methods at any given time during the growing season. This result indicates that the number of E. conspersus recovered in pheromone traps cannot be expected to serve as a direct estimate of the surrounding field population density from week to week during the processing tomato growing season. However, E. conspersus response to pheromone traps was characterized by differential attraction across the sample dates and elevated response early in the growing season relative to the associated field population. Among the most important findings of this work are differential responses of female and male E. conspersus to pheromone traps by crop phenology stage, and the fact that female-biased trap catch coincided with elevated trap response relative to the surrounding field population early in the growing season during tomato vegetative growth through flowering phenology stages. These results, when coupled with further E. conspersus reproductive biology studies, suggest that growers and crop consultants will be able to rely on E. conspersus pheromone trap catch patterns identified in this study to implement pheromone trap monitoring and phenology-based timing of insecticide treatment targeting E. conspersus nymphal stages in processing tomatoes.