SDSU scientists to present findings at switchgrass conference
An entomologist identifying the insects in native grasses is like a kid in a candy store.
"We’re scurrying to beat ourselves, putting out new discoveries,” said entomologist Paul J. Johnson of the South Dakota State University Plant Science Department. SDSU is one of the few research institutions documenting the diversity of insects living on and among native plants like switchgrass, prairie cordgrass and cup plant.
Johnson and grass breeder Arvid Boe have been invited to present their work at the Switchgrass II conference, Sept. 10-12, in Madison, Wis.
Collaborating with Ken Albrecht, a forage agronomist at the University of Wisconsin, Johnson and Boe have recorded 30 different organisms living within native plant ecosystems. Nearly two-thirds of them had never been identified and catalogued.
Impact of insects
Johnson’s presentation will focus on the switchgrass gall midge, a tiny fly that infests the stalk causing 100 percent loss of seed and 40 to 60 percent loss of plant growth, depending on how many stalks, or tillers, of grass are affected.
"Every species of grass has at least one midge in it,” said Johnson. He is examining the life cycle of the switchgrass midge and its relationship to its host plant.
The midge larvae normally spend the winter in the plant tissues, but recently researchers discovered that they are harvested along with the seed when a part of the grain stalk is cut, Johnson explained. Though they don’t eat the seed, the midge could be dispersed to other areas when the seed is subsequently planted.
Potential as a crop
Vance Owens, a professor of plant science and interim director of the North Central Center of the Sun Grant Initiative, said these findings have dispelled the misconception that these native plant species don’t have many natural pests. The important discoveries made by scientists like Johnson and Boe would not have been possible without support from the US Department of Energy Biomass Technologies Office.
Switchgrass is one of the native grasses being considered as an energy crop. The Sun Grant Initiative promotes collaboration among researchers from land-grant institutions, government agencies and the private sector to develop bio-based transportation fuels.
Currently, switchgrass is raised mostly for conservation plantings including erosion control, restoration of wildlife habitat and conservation reserve program. Clint Johnson, owner of Millborn Seeds of Brookings, said a combination of grass species that may include switchgrass is sold for prairie restoration because the diversity helps avoid disease and insect problems.