Siskiyou County WMA

Chair: Jodi Aceves, Senior Deputy Agriculture Commissioner

General contact: Daryl Lara, Vegetation Control Supervisor


Erin Lonergan, Forest Botanist, Klamath National Forest


Meetings: Twice per year at the Siskiyou County Department of Agriculture, Yreka


Outreach Summary:


  • Reprinting and circulation of “Selected Noxious Weeds of Northeastern California” a reference book for weed identification


  • Annual County Fair booth
  • Biennial weed tour throughout county
  • Annual noxious weeds display at Mother’s Day flower show
  • Powerpoint presentations to various interest groups as needed
  • Display booth at July 4th celebration in Mount Shasta City


  • Newspaper insert distributed through several papers in county and at other events.

Project Highlights:

   Knapweed mapping and treatment in western Siskiyou County

  • In order to prevent the spread of knapweed species downstream, where agricultural lands could be impacted, or upslope to forests and rangeland, Siskiyou WMA treated populations of three knapweed species, reducing their density. Spotted, squarrose, and diffuse knapweed were mapped in and adjacent to U.S. Forest Service lands in the western part of the county using GPS/GIS, then mechanically or chemically treated. The acres infested by squarrose knapweed have been reduced from 1,600 acres to 30 acres. This reduction in density will prevent spread by vehicles, cattle, and mining equipment, which are vectors in this area. Project partners include U.S. Forest Service and Siskiyou County Department of Agriculture.

   Eastern Siskiyou County perenial pepperweed control

  • Perenial pepperweed was chemically treated in the Tule Lake and Lower Klamath Federal Wildlife Refuges, in the eastern part of Siskiyou County. Treatments began at the outlying portions of infestations and worked their way towards the center of the infestations. Follow-up treatments are ongoing. Project partners include Tule Lake Irrigation District, the wildlife refuges, private ranchers and farmers, and Klamath County, Oregon.

   Scott and Klamath River leafy spurge biocontrol

  • Siskiyou WMA partnered with California Department of Food and Agriculture, U.S. Forest Service, and Siskiyou County Department of Agriculture to control leafy spurge on Federal land along 60 miles of the Scott and Klamath Rivers. Two species of flea beetles and a longhorn beetle were used as biocontrol agents and were released at many sites along the rivers.

   Musk and Scotch thistle treatment

  • Chemical and mechanical treatments were initiated on a project area of approximately 30,000 acres of Musk and Scotch thistle. Because it is so large, this site was originally designated as a containment and biological control site. The site is predominantly infested with musk thistle, but Scotch thistle has been increasing significantly. Siskiyou County Department of Agriculture partnered with Trinity National Forest to initiate the project.

Organizations on WMA’s MOU

  • Bureau of Land Management, Redding Field Office
  • Bureau of Reclamation
  • Butte Valley Resource Conservation District
  • California Department of Fish and Game
  • California Department of Food and Agriculture
  • California Department of Forestry
  • California Department of Transportation (Caltrans)
  • Klamath National Forest
  • Natural Resources Conservation Service
  • Rocky Mountain Elk Foundation
  • Salmon River Restoration Council, Resource Management
  • Shasta Resource Conservation District
  • Shasta/Trinity National Forest
  • Siskiyou County Department of Agriculture
  • Siskiyou County Farm Bureau
  • Siskiyou Resource Conservation District
  • University of California, Cooperative Extension
  • U.S.Fish and Wildlife Service