Grazing Strategies to Control Medusahead in California

Project Overview

Project Type: Research and Education
Funds awarded in 2006: $138,539.00
Projected End Date: 12/31/2010
Region: Western
State: California
Principal Investigator:

Annual Reports


  • Additional Plants: native plants
  • Animals: bovine, sheep


  • Animal Production: range improvement, grazing - rotational
  • Crop Production: continuous cropping
  • Education and Training: decision support system, demonstration, extension, farmer to farmer, on-farm/ranch research, participatory research
  • Farm Business Management: budgets/cost and returns
  • Natural Resources/Environment: biodiversity
  • Pest Management: competition, weed ecology
  • Production Systems: agroecosystems, integrated crop and livestock systems


    We studied precision grazing to control medusahead. High-density, short-duration grazing when medusahead is at the internode elongation and boot stages dramatically reduces medusahead infestation. In order to achieve satisfactory control, grazing must apply a stocking rate greater than 1 AUM/ac within the two-three weeks when medusahead is susceptible to defoliation. Susceptible phenological stages are between elongation of internodes and milk stake and are predictable, but vary over regions. Barbed goatgrass, another noxious invasive grass, also has late phenology like medusahead, and it is susceptible to defoliation, but it is more resistant than medusahead. Models to forecast readiness for grazing control were not better than predictions based on historic information for each site, although there is some indication that further research can accomplish more accurate forecasting of phenological stages. Based on recommendations from stakeholders, we also tested mowing and non-selective herbicides as additional control tools that can be used with a precision approach. Mowing had dramatic control effect when timed correctly, but it is limited to areas without rocks and that are relatively level. Low-moisture supplement placed in medusahead patches increased grazing intensity and resulted in a reduction of medusahed infestation, but the effects were localized. Detailed study of phenology revealed a bimodal phenology, which could limit control by precise grazing, mowing or herbicide application. Results and approaches were disseminated in several regional and national meetings, and by direct communication with producers. Overall, results underscored the potential for precise timing of management options, but also identified areas that require more detailed investigation such as phenology and chemical interference by medusahed.

    Project participants

    This project was very successful because the work of many collaborators and ranchers. In addition to the gracious and inquisitive ranchers who kindly allowed us to work in their land and who shared their knowledge and time with the group, we had several participants who were part of the core group. These people and their institutions at the time of the project are listed here. They are coauthors of this work and deserve recognition.

    Mel George, Extension Specialist, Plant Sciences MS 1, One Shields Ave., University of California, Davis, CA 95616, 530-752-1720,

    Joseph DiTomaso, Extension Specialist, Plant Sciences MS 1, One Shields Ave., University of California, Davis, CA 95616, 530-754-8715,

    Morgan P. Doran, Livestock & Natural Resources Advisor, University of California Cooperative Extension, 501 Texas Street, Fairfield, CA 94533, 707-435-2459

    John Harper, UCCE Livestock and Natural Resources Advisor, Mendocino and Lake Counties, 890 N. Bush Street, Ukiah, CA 95482-3734, 707-463-4495,

    Stephanie Larson, Livestock & Natural Resources Advisor, Sonoma County, University of California Cooperative Extension, 133 Aviation Boulevard, Suite 109, Santa Rosa, CA 95403, 707-565-2621,

    Sheila Barry, Natural Resources Advisor, UCCE Santa Clara County, 1553 Berger Drive, San Jose, CA 951112, 408-282-3106,

    Bill Frost, UC-ANR Natural Resources and Animal Agriculture Program Leader, Director, UCCE El Dorado County, 311 Fair Lane, ?Placerville, CA 95667, 530-621-5502,

    Josh Davy, Program Representative, ?UC Cooperative Extension, ?Tehama, Colusa, and Glenn Counties, ?1754 Walnut St., ?Red Bluff, CA 96080, 530-527-3101 ext. 5, ?

    Theresa Becchetti, Livestock and Natural Resource Advisor, University of California Cooperative Extension, Stanislaus and San Joaquin Counties, 3800 Cornucopia Way, Suite A, Modesto, CA 95358, 209-525-6800,

    Royce Larsen, Area Watershed / Natural Resource Advisor, University of California Cooperative Extension, 350 N. Main Street, Suite B, Templeton, CA 93465. 805-434-4106 Direct line, 805-781-5940 Front Desk San Luis Obispo Office, 805-434-4881 Fax, 805-781-4316 Fax San Luis Obispo Office,

    Vance Russell, Program Manager, Audubon California, 5265 Putah Creek Road, Winters, CA 95694, 530-795-2921,

    Larry C. Forero, Livestock and Natural Resource Farm Advisor, UCCE, Shasta and Trinity counties. 1851 Hartnell Avenue, Redding, CA 96002-2217,

    Roger Ingram, Acting County Director and Livestock/Natural Resources Advisor, Placer-Nevada Counties, University of California Cooperative Extension, 11477 E Ave., Auburn, CA 95602, Phone: (530) 889-7385, Fax: (530) 889-7397, Email:

    Project objectives:

    Objective 1. Design a simple and cost-effective “precision” grazing method to control medusahead (Mh) and incorporate it into the grazing systems of California annual rangelands.

    Objective 2. Study the effects of spatial distribution of attractants such as supplement on spatial distribution of grazing pressure and use new knowledge to implement supplementation methods to reduce Mh infestations.

    Objective 3. Develop and implement a site-specific and simple system to identify and forecast the period of Mh’s greatest susceptibility to mowing and grazing and establish a warning system for ranchers to accurately time grazing.

    Objective 4. Disseminate, demonstrate and document results in extension fact sheets, field visits and newsletters by Farm Advisors.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.