The tall fescue study was conducted on 60 plots near Bloomington, Ind., that measured 25 square meters apiece. At the start of the 4.5-year study, the land was plowed and planted with fescue seeds that sprouted alongside native grasses. Half of the seeds were tall fescue, which carries the fungal symbiont, and half did not carry the symbiont. The fungus is not transmitted by insects or wind and is only found in plants that sprout from infected seeds.
Half of the test plots were fenced to keep out foraging animals, and half of the unfenced and fenced plots were sprayed with an insecticide to suppress insect herbivores. Tall fescue progressed most slowly in plots that were both sprayed and fenced, constituting about 50 percent of live plant mass in the plots by study's end. In unfenced and unsprayed plots, tall fescue faired best, contributing to 75 percent of the plot by study completion.
"Importantly, we found that more fescue in the unsprayed and unfenced plots was endophyte-infected compared to the plots with herbivore-reduction treatments," said Rudgers "This is significant because it shows that the herbivores actually drive an increase in the relative abundance of infected plants."
In follow-up studies, Rudgers plans to see how tall fescue fares against competitors under drought and non-drought conditions, and she also plans to study symbiotic relationships in native grasses, including some Texas species.
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Contact: Jade Boyd
jadeboyd@rice.edu
713-348-6778
Rice University
29-Aug-2005