Characterization of the arthropod community associated with perennial warm-season grasses (Poaceae) in Nebraska

Switchgrass, Panicum virgatum L., along with two other perennial warm season grasses, big bluestem (Andropogon gerardii Vitman) and indiangrass, (Sorghastrum nutans L), are all recognized as a potential bioenergy feedstock in North America. These stands are high in cellulose, making them a good crop for biofuel. The arthropods associated with these stands are not well known. The arthropods associated with these grasses in a monoculture setting could have the potential to vector various plant viruses or cause direct feeding injury to the plant. The objective of this research was to determine the arthropod complex (i.e., potential pests and beneficial arthropods) associated with these three grass stands. A family-level arthropod survey was conducted in the summer of 2014 and 2015 for all three stand types. Furthermore, a choice study and electronic feeding monitoring were conducted to evaluate the preference among the three stand types to two potential pest species, yellow sugarcane aphid (Sipha flava Forbes) and the greenbug (Schizaphis graminum Rondani). Results from the choice study for S. graminum indicated a significant difference in aphid preference at 1 hours, 2 hours and 4 hours after aphid introduction with the switchgrass population having significantly more aphids than big bluestem and indiangrass. Results from the choice study for S. flava indicated a significant difference in aphid preference after 8 hours, 24 hours, 48 hours and 72 hours after aphid introduction with big bluestem having significantly more aphids than the switchgrass population, but not significantly more than the indiangrass population.