December 27, 2006

Idaho Researcher Uses Fungi on Knapweed

MOSCOW, Idaho -- A University of Idaho researcher is hoping to harness the power of tiny fungi to combat an invasive weed that ranchers blame for crowding out nutritious forage for their livestock.

George Newcombe is busy inside a greenhouse on the school's Moscow campus working with so-called endophytes that live in spotted knapweed, considered one of the West's most-destructive noxious weeds.

Endophytes are found in many plant species and have recently won additional scientific scrutiny. Newcombe says endophytes survive off the host and are believed to boost the plant's survival in exchange for nutrients they provide.

Now, Newcombe says he appears to have been able to isolate an endophyte that renders knapweed sterile. The fungus typically exists in low concentrations, but when it's cultured in a lab and sprayed in higher concentrations, it has a deadly effect.

"They may be the key," Newcombe told the Spokesman-Review newspaper during an interview in the greenhouse of the university's Center for Research on Invasive Species and Small Populations. He's planning field trials soon.

Historical records show the spotted knapweed came from Eastern Europe and Asia into North America about a century ago when it arrived in contaminated crop seed, according to the U.S. Department of Agriculture. With few natural enemies, the perennial with pink to light purple flowers spread across the continent.

It releases a toxin into the soil that can stunt plants that cattle eat. As a result, heavily infested areas often must be reseeded once the spotted knapweed has been eradicated.

As more and more of the West's isolated areas are filled up by the region's burgeoning population, knapweed continues to spread, often along highways, train tracks, power lines and other areas newly being touched by human disturbance.

Endophytes that live on other plants have long been studied. For instance, Taxol, a cancer-fighting drug discovered in yew trees, is a compound produced by endophytes. Some endophytes produce grasses poisonous to grazing animals. Others allow plants to survive in the heated soils around geysers in Yellowstone National Park.

With the recent work on spotted knapweed's endophytes, scientists are beginning to unlock their secrets, said Cort Anderson, manager of UI's Laboratory for Ecological and Conservation Genetics.

"It's helping us understand what gives them the advantage," Anderson said. "It's a very new area of investigation."

The U.S. Department of Agriculture estimates invasive species such as spotted knapweed cost the nation $138 billion annually. Invasive species, including pests like Eurasian water milfoil and New Zealand mudsnails, also choke waterways and rob fish and wildlife of habitat.

In Idaho, the cost of invasives is estimated at $300 million a year, Newcombe said.

While most research to control spotted knapweed has focused on enlisting insects or other pests from its native habitat on the steppe grasslands of western Asia, he says work with endophytic fungi could reap a big payout. It also could add insight to helping control many different types of foreign invaders, he said.

"We need to understand the basic mechanism of invasions or we're never going to get off this treadmill," Newcombe said. "When the source of the next invader could be anywhere, you have to be looking outward."


Information from: The Spokesman-Review, http://www.spokesmanreview.com