Impact of insecticide application and mass trapping on infestation by strawberry sap beetles (Coleoptera: Nitidulidae)

Abstract

The impact of insecticide application and mass trapping on the level of infestation by the strawberry sap beetle, Stelidota geminata Say (Coleoptera: Nitidulidae), was assessed in cultivated strawberry. In total, more than 17,000 adults were captured in traps baited with whole wheat bread dough. Early in the season, captures were similar for traps at the periphery of and within the strawberry field, whereas captures were lowest within the field after fruits had begun to ripen. The presence of peripheral traps slightly increased captures of adults within the strawberry planting, suggesting that mass trapping of adults with food-baited traps may not be a viable management strategy. Applications of fenpropathrin at dusk or mid-day, between the appearance of ripe fruits and the first harvest, reduced infestation of fruits by sap beetle larvae. Fruits located on the ground were more heavily infested by sap beetles than fruits in the plant canopy, which either is due to foraging movements of adults on the ground or reflects differential suitability of strawberry fruits as a food resource for sap beetles. A positive relationship between captures of adults in traps and the abundance of ripe fruits suggests that the spatial distribution of foraging adults is influenced by the availability of food resources.