local weather Click for Sun Valley, Idaho Forecast
 front page
 last week
 express jobs
 about us
 advertising info

 sun valley guide
 real estate guide
 sv catalogs



Produced & Maintained by Idaho Mountain Express, Box 1013, Ketchum, ID 83340-1013 
208.726.8060 Voice
208.726.2329 Fax

Copyright © 2002 Express Publishing Inc.
All Rights reserved. Reproduction in whole or in part in any form or medium without express written permission of Express Publishing Inc. is prohibited. 

For the week of Nov 27 - Dec 3, 2002


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

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)



Mountain Jobs

Formula Sports

Idaho Conservation League



Edmark GM Superstore : Nampa, Idaho

Premier Resorts Sun Valley

High Country Property Rentals

The Idaho Mountain Express is distributed free to residents and guests throughout the Sun Valley, Idaho resort area community. Subscribers to the Idaho Mountain Express will read these stories and others in this week's issue.