BLOOMINGTON, Ind. -- A microscopic fungus that lives inside the most common kind of grass in the eastern United States may be reducing plant diversity throughout its expanding range. The fungus provides competitive advantages for its host, tall fescue, but it is toxic to livestock, wildlife and insects that eat the infected grass. The economic consequences may be as much as a billion dollars a year in the livestock industry alone, and there are other consequences in both agriculture and conservation.
In a report in the Sept. 10 issue of the journal Science, Indiana University biologists Keith Clay and Jenny Holah describe the results of a four-year experiment with tall fescue at the IU Botany Experimental Field. Their study demonstrates that an internal fungus called an endophyte, Neotyphodium coenophialum, often found in tall fescue, can have a major effect on the number of other species persisting in areas where the infected grass grows.
"The infected plants are more vigorous, more toxic to herbivores, and more drought-resistant than uninfected plants," Professor Clay said. "Tall fescue was introduced from Europe in the last century, and it has been widely planted for forage, turf and soil conservation. But it is also a tenacious invader of natural communities, where it can displace native plant species and reduce wildlife populations. Fescue is now the most abundant perennial grass in the eastern United States, and about two-thirds of it is infected with the fungus, which also is not native to North America. The potential effect of the fungus on communities is large, given the abundance and distribution of its host."
Infected grass can't be identified by sight, because the leaves look the same as
uninfected
grass. The fungus lives in the spaces between the plant's cells, and there is no
external sign of
its presence. The fungus infects only fescue, because it spreads only within
seeds of infected
plants. So the fungus is not transmitted to other p
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Contact: Hal Kibbey
hkibbey@indiana.edu
812-855-0074
Indiana University
5-Oct-1999