Tumbling along

 

What smashes into cars on the highway, spreads wildfire and causes painful weltering scratches? It's Russian thistle Salsola spp., more commonly known as tumbleweed, a hard-to-control invasive species that grows in disturbed soil and spreads quickly when the thorny plants break off from the ground and roll along dispersing seeds and piling up along fences and buildings. But now two fungi, one that eats dead plant cells and other that looks like rusty metal, could offer a way to fight back against the troublesome weed.

For 13 years Bill Bruckart and Dana Berner at the Foreign Disease-Weed Science Research Unit of the U.S. Department of Agriculture Agricultural Research Services center in Maryland have been studying the rust fungus Uromyces salsolae and a necrotrophic fungus Colletotrichum gloeosporioides f. sp. salsolae or CGS, which they believe show promise to control Russian thistle. But there are still barriers ahead that could prevent their research from resulting in a breakthrough treatment, including some people's love of the weed as an icon of the American West.

Russian thistle, which came to North America from Europe and Asia over 100 years ago, dries out soil, hosts crop diseases and threatens fences and buildings when it piles up against them ready to burn. Today there are at least six species occupying as much as 100 million acres of disturbed land, especially in arid Western states. Previous efforts using insect control to slow the invasive's spread have had little effect.

"Many of the introduced pests in the US have come in without their full complement of natural enemies," USDA's Bruckart explains. So researchers look for solutions in the plants' native habitat, eastern Europe and Russia. After finding pathogens that preyed on tumbleweed, the researchers studied them in a sealed greenhouse in the US. They spent decades testing whether the pathogens could harm more than 60 species of other plants to see if there was risk of the fungi infecting non-target species. They also conducted field studies in the country of origin, comparing plots of healthy tumbleweed with infected plots. In one such study in Greece, CGS killed nearly 100 percent of tumbleweed in a plot over two years.

Now that they have found likely fungal candidates for invasive control, the researchers are seeking regulatory approval from USDA's Animal and Plant Health Inspection Service. But despite the scientific evidence in favor of the release, regulators are hesitant to authorize application of the pathogens unless the public convinces them it's necessary. "The regulators are super risk averse," says Berner. "If there is no push from the end user, they find no need to be proactive."

Pushing back against their efforts is the image of tumbleweed as Western icon, complete with a whistling soundtrack and gunmen reaching for their six shooters at high noon. If you're feeling nostalgic for the wild West, you can buy your very own Huge Tumbleweed online for $39 plus $50 shipping and handling at buytumbleweednow.com. One online store selling "decorative dried wheat, plants, and grasses" promises, "For every dollar donated, Curious Country Creations will spread seeds so that tumbleweeds can continue with the history of the west [sic]."

The researchers hope public opposition to the invasive overcomes the nostalgia, and that regulators understand the need for the tumbleweed-terminating fungus. "(We) get frustrated with regulators," says Berner. The petition for the rust fungus has been awaiting approval for more than a year. He hopes those who have experiences with tumbleweed's destructive nature will "provide testimonials on how badly they do need" a bio-control.

"Tumbleweed is a big issue in the West," adds Bruckart.

Even if they get their permit to release fungus on the invasives, the researchers can't predict how effective the treatments will be as a control. "If it's too cold or too hot it doesn't work," Bruckart explains. Pathogens have been applied in Australia and other countries to successfully put a damper on invasive species, though, and Berner and Bruckart hope their work will achieve similar results in the Western U.S.

"The CGS would be a breakthrough I'm convinced," says Berner. "[It's] a darn good pathogen to control tumbleweed."

 

Tumbleweed image courtesy Flickr user Denise Rowlands.

Map of counties affected by Salsola tragus, one common species of Russian thistle, from Early Detection & Distribution Mapping System at the University of Georgia - Center for Invasive Species and Ecosystem Health. Available online at http://www.eddmaps.org/.

Emilene Ostlind is an editorial fellow at HCN.

High Country News Classifieds
  • NEWS DIRECTOR
    Based in the state capitol, Boise State Public Radio is the premier NPR affiliate in Idaho. With 18 transmitters and translators, it reaches 2/3rds of...
  • INTERNET-BASED BUSINESS FOR SALE
    Dream of owning your own business, being your own boss, working from home ... this is the one.
  • EXECUTIVE DIRECTOR FOR MOJAVE DESERT LAND TRUST
    Organization Background: The Mojave Desert Land Trust (MDLT) is a non-profit 501(3)(c) organization, founded in 2006. Our mission is to protect the ecosystems of the...
  • EXECUTIVE DIRECTOR
    If you are deeply committed to public service and would like to become part of our high performing, passionate and diverse team, NCAT is looking...
  • TRIPLEX .8 ACRE KANAB, UT
    Create a base in the center of Southern Utah's Grand Circle of National Parks. Multiple residential property with three established rental units and zoning latitude...
  • FORGE & FAB SHOP
    with home on one beautiful acre in Pocatello, ID. Blackrock Forge - retiring after 43 years! Fully equipped 5,500 sf shop including office, gallery and...
  • SMALL FARM AT THE BASE OF MOUNT SHASTA
    Certified organic fruit/berry/veggie/flower farm. Home, barns, garage, separate apt, more. Just under 2 ac, edge of town. Famously pure air and water. Skiing, mountaineering, bike,...
  • FOREST STEWARDSHIP PROJECT DIRECTOR
    Become a force for nature and a healthy planet by joining the Arizona Chapter as Forest Stewardship Project Director. You will play a key role...
  • EXECUTIVE DIRECTOR
    Ranchers Stewardship Alliance is accepting applications for an Executive Director. This position will provide leadership to RSA, develop a fund raising plan, and effectively communicate...
  • WRITING PLACE: THE ANIMAS RIVER REGION WRITING WORKSHOP
    REGISTER ONLINE BY: Friday, June 15 WHERE: Durango, CO (location TBD) WHEN: Monday, July 16 Youth workshop: 10 a.m. - 12 p.m. (18 and under,...
  • EQUITY IN THE OUTDOORS COORDINATOR
    The Equity in the Outdoors Coordinator will lead community engagement, program implementation and development, and data collection for the Eagle Valley Outdoor Movement (EVOM). EVOM...
  • COMMUNITY ENGAGEMENT ASSISTANT
    The Idaho Conservation League is seeking a personable individual who is passionate about conservation to join our Sandpoint Field Office. The Community Engagement Assistant will...
  • LIGHTWEIGHT FLY ROD CASES
    4 standard or custom lengths. Rugged protection for backpacking. Affordable pricing.
  • EXPERIENTIAL EDUCATION INTERN/ASSISTANT
    Actively introduce students to Experiential Education, Outdoor Recreation, and Sustainability while engaging and challenging them to learn and participate in these diverse opportunities. Room, board,...
  • ENVIRONMENTAL INVESTIGATIVE MEDIA SERVICES
    In-depth investigations of polluters, lobbyists, regulators, elected officials and others focused on environmentally damaging projects in the U.S. and internationally. We specialize in mining projects,...
  • UNDEVELOPED 40 ACRES - SOUTHWEST COLORADO
    in beautiful Montezuma County.
  • TRUCK DRIVER
    Class A & B drivers, pass all DOT requirements and clean driving record
  • MARIA'S BOOKSHOP FOR SALE
    - Thriving Indie bookstore in the heart of Durango, Colorado. General bookstore with 34-year history as a community hub for Southwest region of CO. 1800...
  • ASSOCIATE DIRECTOR OF DEVELOPMENT
    HawkWatch International seeks an experienced fundraiser to join our awesome team! This position will provide support in all aspects of the department. We are looking...
  • DIRECTOR OF DEVELOPMENT
    will develop and execute Wild Utah Projects fundraising plan. Call, email or check full description of job online for more details: