European Chafer Grub Feeding on Warm-season and Cool-season Turfgrasses, Native Prairie Grasses, and Pennsylvania Sedge

Abstract

Six grass species representing vegetative and seeded types of native, warm-season and cool-season grasses, and pennsylvania sedge (Carex pensylvanica) were evaluated in the greenhouse for resistance to root-feeding grubs of european chafer (Rhizotrogus majalis). Potted bermudagrass (Cynodon dactylon), buffalograss (Buchlöe dactyloides), zoysiagrass (Zoysia japonica), indiangrass (Sorghastrum nutans), little bluestem (Schizachyrium scoparium), tall fescue (Festuca arundinacea), and pennsylvania sedge grown in a greenhouse were infested at the root zone with 84 grubs per 0.1 m2 or 182 grubs per 0.1 m2. The effects on plant growth, root loss, survival, and weight gain of grubs were determined. Survival rates were similar for low and high grub densities. With comparable densities of grubs, root loss tended to be proportionately less in zoysiagrass and bermudagrass than in other species. European chafer grubs caused greater root loss at higher densities. Grub weight gain and percentage recovery decreased with increasing grub density, suggesting a food limitation even though root systems were not completely devoured. Bermudagrass root weight showed greater tolerance to european chafer grubs; another mechanism is likely involved for zoysiagrass. Variation in susceptibility of plant species to european chafer suggests that differences in the ability of the plants to withstand grub feeding damage may be amenable to improvement by plant selection and breeding.