Perennial grasses could become popular biomass crops in the future. Many perceive these grasses require little to no management for insects or other pests. However, researchers are finding rather than being pest-free, the identity of insect pests and their effects on harvestable biomass are simply not yet known.
A small caterpillar known as the tiller-killer has been documented in switchgrass across the Midwest by a team of researchers at the Energy Biosciences Institute at the University of Illinois. In addition, this team has recently identified fall armyworms, corn leaf aphids and yellow sugarcane aphids as potential pests of Miscanthus x giganteus.
Mike Gray, a U of I entomologist leading this team of researchers, says, "Our goal is to discover perennial grass pests now so we can study their potential impact before these grasses become widespread. However, finding insects does not necessarily indicate a problem."
Fellow team member Jarrad Prasifka, a U of I post-doctoral research associate, presented their team's research and goals at the Bioenergy Feedstocks Symposium in Champaign on Jan. 11. For the past two years, they have been conducting surveys and searching for pests on biomass crops.
"As biomass production increases, pests will react to the new resources we put out and make available to them," Prasifka adds. "In the United States, soybeans were considered a pest-free crop for many years. But now, soybeans, just like any other crop, have management issues related to both insects and diseases."
Prasifka said it's hard to forecast the effects of pests on perennial biomass crops.
"If you were to ask me what the outlook on a certain pest is for next year, I might be able to make a good prediction," he explains. "But if you are looking 10 more years down the line at Miscanthus, that's very difficult to do. We are talking about a scale of time that actually permits evolution of insect and pathogen populations."