Location: Corn Host Plant Resistance ResearchTitle: Belowground resistance to western corn rootworm in Lepidopteran-resistant maize genotypes Author
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/26/2010
Publication Date: 2/1/2011
Citation: Gill, T., Sandoya, G., Williams, W.P., Luthe, D.S. 2011. Belowground resistance to western corn rootworm in Lepidopteran-resistant maize genotypes. Journal of Economic Entomology. 104:299-307. Interpretive Summary: Feeding on corn by southwestern corn borer, fall armyworm, and other Lepidoptera can cause substantial losses. Plant resistance is generally considered a desirable method of reducing these losses, and several corn germplasm lines with resistance to these Lepidoptera have been developed and released by USDA-ARS at Mississippi State. In this study, corn genotypes with resistance to southwestern corn borer and fall armyworm were evaluated for resistance to two insects that feed on the roots: western corn rootworm and southern corn rootworm. The results of the investigation indicated that survival of both western and southern corn rootworm was significantly lower on corn genotypes that are also resistant to fall armyworm and southwestern corn borer. Furthermore, feeding by fall armyworm on above-ground portions of the plants of some genotypes reduced survival of western corn rootworm in the root tissues. Feeding by western corn rootworm on the roots also appeared to enhance resistance to fall armyworm. These results indicate that intra-plant communication alters the plant’s response to both aboveground and belowground pests.
Technical Abstract: Several maize inbred lines developed from an Antiguan maize population have been shown to exhibit resistance to numerous aboveground lepidopteran pests. This study shows that these genotypes are able to significantly reduce the survival of two root feeding pests, western corn rootworm (Diabrotica virgifera) and southern corn rootworm (Diabrotica undecimpunctata). The results also demonstrated that feeding by the aboveground herbivore (Spodoptera frugiperda – fall armyworm) prior to infestation by western corn rootworm reduced survivorship of western corn rootworm in the root tissues of some, but not all, genotypes. Likewise, the presence of western corn rootworm in the soil appeared to increase resistance to fall armyworm in the whorl in several genotypes. However, genotypes derived from the Antiguan germplasm with genetic resistance to lepidopterans were still more resistant to the fall armyworm and both rootworm species than the susceptible genotypes even after defense induction. These results suggest that there may be intraplant communication that alters plant responses to aboveground and belowground herbivores.