Seeds of
destruction spread
County
counterattacks noxious weeds
"The
worst thing you can do is spray knapweed with something like Roundup and
kill everything there. Then, in a couple of years, you’ve got nothing
but knapweed."
JOHN
CENARRUSA, Blaine
County weed
superintendent
By GREG
MOORE
Express Staff Writer
A
counterattack against Blaine County’s noxious weed invasion has been
under way by the county weed superintendent, federal land management
agencies and private landowners, especially farmers.
But
despite increasing eradication efforts, the battle is probably a
permanent one. The weeds will never be completely wiped out, and one
survivor can quickly re-seed a large area. In addition, new seeds are
constantly arriving, carried on the wind, in the coats of animals and on
vehicles.
Under
state law, all landowners are required to eradicate noxious weeds on
their property. At least, that’s the theory. The reality is not so
simple—the weeds are too widespread, and rigorous enforcement would be
a major undertaking.
Blaine
County Weed Superintendent John Cenarrusa said the county sends a few
dozen letters each year to private landowners informing them of the
existence of noxious weeds on their property, and of their obligation to
eradicate them. Those who do not comply can be billed for the county’s
cost of doing the work itself. Most recipients, Cenarrusa said, are
unaware of the situation.
"When
they find out there’s something that’s threatening the quality of
life here, they want to get right on it and clean it up."
Cenarrusa
said the biggest local problem is the spread of noxious weeds from
federally managed land to county and private land. However, neither the
U.S. Forest Service nor the Bureau of Land Management has the funding to
eradicate all the noxious weeds on the land they manage. Seth Phalen,
range land management specialist with the Sawtooth National Recreation
Area, said allocating resources is a triage situation—the first
priority, like putting out spot fires, is to eradicate new invaders. The
second is to contain large patches and the third, when extra money is
available, is to begin shrinking them.
He said
the Forest Service generally sprays herbicide on between 100 and 200
acres of weeds, mostly spotted knapweed, on the SNRA each year. But due
to the addition of a two-man spraying crew last summer, Phalen said,
about 400 acres were sprayed.
"We’ve
been successful in maintaining a weed-free zone along the highway from
Easley Creek up to Stanley," he said.
South of
Easley it’s another story. Spotted knapweed has taken over about 200
acres between there and the SNRA headquarters at North Fork. County and
Forest Service crews sprayed about half that area this summer.
"We
want to start aggressively thinning out the infestation that’s
there," Phalen said.
The BLM
has been using helicopters to spray large patches of leafy spurge south
of Carey. Since it has a deep root system, the plant has been
out-competing the native plants grazed by livestock and wildlife, and
invades rapidly after range fires. However, its hardiness is also its
undoing. By remaining green in mid summer, the patches are a readily
visible target from the air.
The BLM
has also been spraying spotted knapweed along roads in south-county side
canyons. However, that has become more difficult as the plants slowly
spread up hillsides. Out of reach of the trucks, plants growing there
need to be treated by people with backpack sprayers—a far more
expensive undertaking.
Another
problem is that hillsides are more difficult to re-seed.
"That’s
the next problem," said Shoshone District Fire Use Specialist Joe
Russell. "If the ground doesn’t have some type of cover to
compete against them, there’s a good chance the weeds will just come
back."
Those
involved consider the long-time use of herbicides to be an unfortunate
necessity.
"The
weeds are a man-created problem," said south-county farmer Larry
Schoen. "You need to use management to solve this problem. The way
that farmers use chemicals today, which are very plant-specific, is far
less of an environmental threat than the noxious weeds are."
The
environmental safety of herbicide use depends largely on the care of the
person using them. Done correctly, they are applied in very small
quantities—only one-half pint to one pint per acre.
"The
worst thing you can do is spray knapweed with something like Roundup and
kill everything there," Cenarrusa said. "Then, in a couple of
years, you’ve got nothing but knapweed."
Though
herbicides are viewed as the best way to stop a nascent weed
infestation, an alternative increasingly pursued for long-term control
is biological¾the use of insects from the weeds’ native habitat that
will eat them. The method has advantages beyond eliminating the use of
chemicals. Once they are established, the insect populations become a
permanent part of the ecosystem. Optimally, they chow down on enough
plants to keep them under control, but their natural population cycles
ensure that they won’t eliminate their food supply.
One such
program was the Camas County Bio Control Project, which paid local teens
$6 an hour for the past five summers to release five species of
insects¾weevils native to the eastern Mediterranean¾and to monitor the
results. Forest Service entomologist Rob Progar, who supervised the
crew, said the bugs reduced noxious weeds by about 75 percent in the
areas they were released. He said that to be most effective, the
technique requires regular maintenance, using specific insects to target
different parts of the plants at different times of the year.
"It’s
kind of like grazing sheep, only you’re grazing your insects."
Pointing
out that nothing will permanently eliminate the weeds, he believes
biological methods are a better long-term solution than are herbicides.
"Usually,
once you’ve got a weed established, you’ve got it," he said.
"Then you need to be concerned about keeping the weed in balance
with native vegetation. The insects reduce the plants’ vigor enough
that native vegetation can compete."
The
obvious next question is, "What do you bring in to kill the bugs
when they become a worse problem than the weeds?"
Lou
Dersch, a Twin Falls field officer with the U.S. Department of
Agriculture’s Plant Quarantine and Protection, said the department is
well aware of that hazard. He said each of the 64 weed-eating insect
species on its list of "approved biological control agents"
has gone through a multi-year screening process to make sure that it
eats only the targeted plants.
Progar is
now writing a proposal to obtain cost-sharing money from the Idaho
Department of Agriculture to expand the Camas County bug crew to Blaine
and Elmore counties next summer.
A second
natural form of weed control that so far has received little attention
is grazing by goats. A business in Jackson, Wyo., called Ewe4ic
Ecological Services, rents weed-chomping goats for $1 per goat per day.
The goats, which can tolerate many plant species that are toxic to other
livestock, not only eat the weeds but add natural fertilizer for
re-seeding as well. According to the business, the goats don’t like
grass. Two years ago, the city of Vail, Colo., hired a herd of goats to
graze noxious weeds in an ecologically sensitive area along the Eagle
River.
(Next
week: Blaine County’s Strategic Plan)