Landscape factors affect relative abundance of rootworm species and pod injury in Georgia peanuts.

Abstract

The southern corn rootworm, Diabrotica undecimpunctata howardi Barber, is native to the US where it is a pest of peanut, Arachis hypogaea. The banded cucumber beetle, Diabrotica balteata LeConte, is native to the neotropics, but its range has expanded and currently includes most of the US peanut production area. The purpose of this study was to: (i) define seasonal variation in adult rootworm populations in peanut fields, and (ii) determine the effect(s) of proximity to a putative early season host (i.e., corn, Zea mays) and the presence of irrigation on rootworm infestation and pod injury 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 180 m from the field edge in irrigated and nonirrigated peanut fields with and without a corn border. Two peaks in abundance were observed for both species in each year. Though peak abundance for the two species occurred nearly simultaneously, D. balteata was more abundant than D. u. howardi. Beetle abundance was highest in fields bordered by corn, but presence of irrigation was not as important for D. balteata as it was for D. u. howardi. Pod injury was greater in fields bordered by corn in both years, but there was no difference in pod injury between irrigated and nonirrigated fields. The number of beetles captured and incidence of pod injury within a field did not differ with distance from the field border.