Trichogramma Brassicae and SLAM®, an Integrated Approach to Managing European Corn Borer and Corn Rootworms

Abstract

European corn borer, Ostrinia nubilalis (Hubner) (Lepidoptera: Crambidae); western corn rootworm (WCRW), Diabrotica virgifera virgifera LeConte; and northern corn rootworm (NCRW), Diabrotica barberi (Smith & Lawrence) (Coleoptera: Chrysomelidae) are important pests of corn, Zea mays L., that occur simultaneously in the US Corn Belt. Areawide management strategies for northern and western corn rootworm in Iowa, Kansas, South Dakota, Illinois, and Indiana, and for the Mexican strain in Texas, use SLAM®, which contains cucurbitacin, a feeding stimulant, and a small amount of the insecticide carbaryl. This management strategy is environmentally sound because it introduces a substantially lesser amount of chemical insecticide into the environment than prophylactic soil insecticide applications for WCRW management. To develop a management program for both corn pests, the compatibility of SLAM® to control CRW, along with a biological agent to manage European corn borer, was investigated. Laboratory studies were conducted using the egg parasitoid Trichogramma brassicae (Bezdenko) (Hymenoptera: Trichogrammatidae). In experiments in which SLAM® and T. brassicae were evaluated as components of a management system, SLAM® did not affect parasitism or parasitoid emergence rates. Trichogramma brassicae displayed vigorous biotic fitness, emergence rates, sex ratios, and fecundity over the duration of the study. Data collected under these laboratory conditions indicated that SLAM® had no adverse effect on the quality of T. brassicae, indicated by its ability to reproduce in the filial generation.