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
This article appeared in the print edition of the magazine with the headline A cheatgrass antidote – maybe.
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