| Cont.:Section four: noxious weed control |
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| Special projects for 2007 |
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The Noxious Weed Control Program works on a variety of special projects and with a host of public and private cooperators to implement noxious weed control projects throughout the state. The following are a few of the projects completed in 2007:
WeedMapper project
WeedMapper (www.weedmapper.org) is a Web site that provides distribution maps and information on identification and impacts of state listed weeds. It also provides a report form to allow cooperators and land managers to notify ODA of any new weed sightings. Weeds are mapped at the state and county levels. This is a joint project between ODA and OSU with support from BLM, and USFS.
Weed maps are compiled from data provided by ODA, USFS, BLM, county weed programs, SWCDs, cities, non-profit groups, and online submissions. Data contributed to WeedMapper continued to increase in 2007, 68 agencies and property managers contributed. Extensive effort was put into organizing and consolidating data this year to make the transition from raw data to published maps smoother and quicker.
WeedMapper is a valuable tool in EDRR efforts. Shared data turned up a new record of garlic mustard (a “T” listed weed) in Jackson County and a citizen used the weed siting form to report a new location of giant hogweed. The Web site also prompts users to call the Invasive Species Hotline to report high-priority weeds.
Reports from users continue to be overwhelmingly positive. The Web site is being used by a wide range of land managers from federal, state and local agencies to assess conditions and prioritize projects. The site is also used by property owners who are looking for information about weed identification and distribution and students researching weed information for projects and reports.
Progress was also made on securing a data-collection device that will allow users to collect and share field survey data easily. The TDS Recon, a sturdy PDA, was tested in 2007 and will be used by ODA in 2008. If field tests of the PDA and WeedMapper Data Collection software goes well the program will be made available to other agencies to collect WeedMapper data.
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| Biological control |
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Since 1947, 71 species of classical biological control agents have been introduced against 27 species of noxious weeds in Oregon. Several of these biocontrol agents have become reassociated with six additional species of weeds for which they were not originally introduced. ODA manages 112 biocontrol projects, the most of any state in the US. The ODA biocontrol database contains more than 11,700 records of biocontrol agent releases. Several biocontrol projects have been successful in controlling targeted weeds, including tansy ragwort, St. Johnswort, musk thistle, Mediterranean sage, purple loosestrife, yellow starthistle, diffuse knapweed, and Dalmatian toadflax. ODA strives to adhere to the International Code of Best Practices for classical biological control of weeds in order to better implement a safer and more effective program.
Chart: Biocontrol agents and weeds: Cumulative number of weeds targeted (gray) and cumulative number of classical biological control agents (black) released in Oregon by year.
Biological agents were released at more than 264 sites in Oregon during 2007, treating over 3,000 acres. Over 144 biocontrol sites were monitored to determine establishment and impact of biocontrol agents. In April 2007, Staff Entomologist Eric Coombs attended the XII International Symposium Biological Control of Weeds in La Grande Motte, France. He presented two papers and co-authored two others.
The USDA APHIS-PPQ biocontrol program, under the direction of Gary Brown, remains an important partner in implementing biocontrol in Oregon. ODA and APHIS provide surplus biocontrol agents to many local agencies and other states. The ODA program continues its work on cooperative research projects with Drs. Peter McEvoy and Jeff Miller and their staff at OSU. The ODA Biocontrol Program also serves as the state level biological control of weeds data center for the US.
Major projects
Dalmatian toadflax: The toadflax stem weevil Mecinus janthinus has been recovered in many locations in central and eastern Oregon and provides excellent control. A cooperative project with county weed programs, ODA, and BLM released weevils along 30 miles of the John Day River and other areas in the river basin.
Field bindweed: The field bindweed gall mite Aceria malherbae was found established in Oregon for the first time. A healthy population of mites was recovered in the Tygh Valley area in Wasco County, where the mite reduced the biomass of field bindweed by more than 80 percent. Redistribution efforts were made at the local site in order to provide a larger nursery habitat that could be used for redistribution to other parts of the state in 2008.
Garlic mustard: In 2006 ODA began pre-release monitoring studies in conjunction with Dr. Bernd Blossey, Cornell University, NY. Host specificity testing is currently underway and releases could be made in the next year or two.
Gorse: In 2007 petitions were submitted to import and test the gorse shoot moth Agonopterix ulicitella and the gorse thrips Sericothrips staphylinus at the OSU Quarantine Facility. Field sampling near Hilo, HI was conducted in 2007. Collection sites for both agents were established for host specificity tests planned in 2008. The project is being coordinated by Dr. Fritzi Grevstad, funded by USFS. ODA is a major partner.
Knotweeds: Prerelease studies on Japanese knotweed and its allies were conducted at several sites in Oregon in cooperation with ODA. The quarantine facility at OSU, Forestry Sciences, is being used to conduct host specificity studies for several prospective biocontrol agents (Ostrinia, Galerucida). The project is being coordinated by Dr. Fritzi Grevstad (University of Washington) and primarily funded by USFS. ODA is raising host test plants.
Meadow knapweed: Redistribution of the knapweed seedhead weevil Larinus obtusus is nearly completed in western Oregon. Studies to determine efficacy will be conducted in the coming years, and releases will be made as needed.
Mediterranean sage: An ongoing cooperative study with Dr. Jeff Miller, OSU, Department of Range Science, is studying the regional long-term impacts of the root/crown weevil Phrydiuchus tau on Mediterranean sage. Most ODA release sites from 1970-1983 have shown significant control and an $800,000 per year benefit, especially at sites now dominated by perennial grasses and shrubs. Results from long-term regional studies were submitted for publication in 2007. ODA will study a major outbreak of Mediterranean sage as part of a team with cooperators. The outbreak in the Summer Lake area resulted from a fire several years ago.
Purple loosestrife: The Galerucella leaf beetles have reduced numerous infestations throughout Oregon by more than 90 percent. A cooperative project with APHIS; Dr. Ralph Garono, Earth Designs Inc.; and Dr. Peter McEvoy, OSU will monitor and redistribute the agents throughout the lower tidal zones of the Columbia River area.
The Army Corps of Engineers provided funding for a mass-rearing project, which supplied releases of the root weevil Hylobius transversovittatus for sites along the Columbia River. Many stands are of loosestrife are in decline following severe defoliation by the leaf beetles.
Rush skeletonweed: The root-boring moth Bradyrrhoa gilveolella was released in the Port of Portland area within the BPA power line right-of-way. Additional population sources from Europe are being sought that are more adapted to southwest Oregon conditions.
Russian thistle: Russian thistle seeds were collected at several sites in Oregon. USDA-ARS will test the vulnerability of Oregon Russian thistles to various pathogens from Europe, which may be potential biocontrol agents.
Salt cedar: The leaf beetle Diorhabda elongata has been difficult to establish in Oregon. In 2007, Gary Brown, USDA-APHIS, gave ODA approximately 50,000 adult beetles from Lovelock, Nevada. The beetles were released at several sites in Malheur County. By August, the beetles had defoliated a strip 30 meters long at the Haystack Butte site, the first site to show a promise of possible establishment.
Scotch broom: The Scotch broom gall mite, Aceria genistae, was discovered in 2005 near Portland, Oregon. This was the first finding of this adventive natural enemy of Scotch broom in the US. ODA is cooperating with Jennifer Andreas, WSU, to conduct host specificity studies to determine if the mite is safe enough for redistribution into new areas. Also, the Scotch broom seed beetle Bruchidius villosus has been widely redistributed for the first time, and should continue for the next several years.
Tansy ragwort: In 2005 numerous sites in the Willamette Valley experienced a resurgence of tansy ragwort. Biocontrol agents were found at all of the recalcitrant infestations. No livestock deaths associated with the 2005-2007 outbreaks have been reported to ODA. A cooperative study with the University of Idaho is being conducted to test the Swiss biotype of the flea beetle at various elevations in Oregon and Idaho. An open release was made in eastern Oregon at the Buckhorn infestation.
Teasel: Preliminary investigations are being conducted on two species of teasel to survey for natural enemies. The investigations are conducted in cooperation with USDA-ARS EBCL.
Economic benefits
Classical biological control of weeds has a good safety record, but a somewhat scanty track record of documented economic benefits. Most of funding for biocontrol projects is used during the foreign exploration host specificity testing in the introductory phase, and little is appropriated for long-term efficacy studies. On successful long-term projects, benefits can occur as steady stream returns, i.e., $5 million per year for the ragwort project in Oregon, where annual agency expenditures on this weed is now less than $20,000 per year.
Where feasible, it is economically advantageous to implement biocontrol in order to reduce annual losses. By actively redistributing ragwort biocontrol agents, ODA accomplished a successful regional project five to 10 years sooner than by the natural spread of the insects, averting $25-$50 million in losses to agriculture.
A partially successful biocontrol project can provide a positive benefit-cost ratio, even though the degree of weed control may be less than desired. If biocontrol agents reduced the top 12 weeds by 30 percent, annual losses could decrease by $20 million. A 10 percent reduction of Scotch broom alone by biocontrol agents would yield $1.5 million in annual benefits.
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