Response of bioenergy switchgrasses (Panicum virgatum L.) to Greenbug (Schizaphis graminum (Rondani)) and Yellow Sugarcane Aphid (Sipha flava (Forbes)) herbivory

Switchgrass, Panicum virgatum L., is a perennial plant native to North America that is being developed as a potential biofuel resource.   A number of aphids, including greenbugs, Schizaphis graminum (Rondani) and yellow sugarcane aphid, Sipha flava (Forbes), have been identified as potential pests of switchgrass.  Feeding by these insects on plants can elicit a number of stress-related responses.  These can include an increase in the levels of enzymes such as peroxidases and catalases and reactive oxygen species, such as hydrogen peroxide, within the plant cells.  This research investigated the accumulation of reactive oxygen species and peroxidase in greenbug- and yellow sugarcane aphid-infested plants in resistant and susceptible switchgrass populations.  Susceptible switchgrasses showed increased accumulation of hydrogen peroxide as well as an increase in peroxidase enzyme activity in response to aphid feeding.  Greenbug exposure to resistant switchgrass plants resulted in an increase in peroxidase activity. No differences were detected in hydrogen peroxide accumulation in the resistant genotypes when exposed to greenbugs.