A cheatgrass antidote - maybe

  The federal Bureau of Land Management wants to send the message that cheaters never win, and that goes for cheatgrass, too. The agency's weapon of choice is Oust, a controversial DuPont herbicide.

Last fall, BLM range specialists with the Snake River Birds of Prey National Conservation Area in Idaho found that in early tests, Oust kills the weed, but not native plants. Officials say the chemical - which DuPont has been testing since 1981 - may be their first powerful tool against a noxious weed that has been wreaking ecological havoc on Western rangelands for a century.

Cheatgrass, an annual introduced from Eurasia, spreads quickly, robbing soil of moisture and nutrients necessary for native plants. The grass turns diverse landscapes into cheatgrass monocultures vulnerable to wildfire.

Oust kills cheatgrass, or any plant, by preventing cell division. The key for range managers, say DuPont officials, is to apply Oust in the right quantity that kills only targeted weeds.

But Oust may have hidden, long-term effects on the plants it doesn't kill, says Caroline Cox of the Northwest Coalition for Alternative Pesticides in Eugene, Ore. Oust is so toxic, she says, that it's only used in ounces per acre, and "plants are damaged at (herbicide) levels not detected in laboratory analysis."

BLM range manager Steven Jirik says caution is the point of the agency's field tests, which have found that Oust so devastates native-plant seed banks that range managers must wait six months before reseeding areas where Oust has been applied. Jirik says they'll continue testing Oust on the Birds of Prey Conservation Area before applying it across the West. So far, he adds, "the results are pretty phenomenal."

* Jamie Murray,

Peter Chilson

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