Hunting billbug (Sphenophorus venatus vestitus) adult feeding preference and host volatile recognition

The transition zone in the U.S. is widely regarded as one of the most challenging places to manage warm- and cool-season turfgrasses. Global climate change may result in an expansion or shift in this zone, exposing turfgrass pests to new host species and potential expansions in geographical range. Sphenophorus venatus vestitus is a pest of both warm- and cool-season turfgrasses, but damage is most often cited in the warm-season turfgrasses, zoysiagrass (Zoysia spp.) and Bermudagrass (Cynodon spp.).  The objectives of this research were to determine (1) adult feeding preference for warm- vs. cool-season turfgrasses, (2) preference for specific warm-season grasses (Bermudagrass vs. zoysiagrass), and (3) adult behavioral responses to host plant volatiles. Objectives one and two were accomplished through laboratory feeding choice assays incorporating Bermudagrass, zoysiagrass, Kentucky bluegrass (Poa pratensis), tall fescue, (Festuca arundinacea), and creeping bentgrass (Agrostis palustris). The number of adult feeding punctures on a tiller at 24, 48, and 72 hours was used as a quantitative indicator of host preference. There was no significant preference for warm- vs. cool-season turfgrasses. However, there was a significant preference for zoysiagrass compared to Bermudagrass. Response to host plant volatiles is being currently being investigated using binary choice y-tube olfactometer assays that include the same turfgrass species used for objectives one and two. Insight into the host preference and chemical basis of this preference in S. venatus vestitus may improve integrated pest management programs by enhancing the utility of monitoring and decreasing dependence on chemical insecticides.