Adjacent crop and irrigation affect rootworm abundance and injury in peanut

The southern corn rootworm, Diabrotica undecimpunctata howardi, is native to the US where it is a serious pest of peanut. The banded cucumber beetle, D. balteata, is native to the tropics, but its range has expanded and currently includes most of the US peanut production area. The purpose of this study was to define seasonal variation in adult rootworm populations in peanut fields and to determine if proximity to a putative early season host (i.e. corn) contributes to infestation in peanut. Seasonal abundance of adult rootworms in commercial peanut fields in Georgia was monitored in 2021 and 2022 using plant volatile lures attached to yellow sticky traps. Traps were located at 45, 90 and 180m from the field edge in peanut fields with and without a corn border. Approximately half of the fields in each border treatment group were irrigated. Two peaks in abundance were observed for the two species in both years. Though peak abundance for the two species occurred nearly simultaneously, D. balteata was much more abundant (approximately 8x) than D.u. howardi. Beetle abundance was higher in fields bordered by corn and in irrigated fields. Pod injury was greater in fields bordered by corn in both years but only differed in irrigated versus non-irrigated fields in 2022. The number of beetles captured and incidence of pod injury did not differ with distance from field borders.