Print Friendly and PDF


Advanced Search Results Detail

Project ID: 11-S-2-6

Year: 2012

Date Started: 06/01/2012

Ending Date:  05/31/2015

Title: Enhancing the Effectiveness of Annual Grass Weed Biocontrol with the Seed Pathogen Black Fingers of Death (Pyrenophora semeniperda) on Intermountain Rangelands

Project Proposal Abstract: Annual brome infestation, especially cheatgrass (Bromus tectorum) infestation, is a major contributing cause of environmental degradation on tens of millions of hectares of semiarid rangelands in the Interior West, where repeated burning often results in conversion to annual grass-dominated systems. Annual brome monocultures are very difficult to restore to more desirable perennial vegetation without some form of control, and even effective control of existing annual brome stands can leave behind high seed densities in the persistent seed bank. Our project has the primary goal of developing a biocontrol method that specifically targets these dormant, ungerminated seeds. The fungal seed pathogen black fingers of death (Pyrenophora semeniperda) kills thousands of seeds per square meter every year in seed banks of weedy annual bromes, even at naturally occurring levels. We have shown that augmentation with artificially produced inoculum of this pathogen can result in elimination or near-elimination of the annual brome persistent seed bank. Use of this biocontrol agent in combination with herbicides that eliminate germinated seeds or plants can result in essentially complete control. A second goal of our research is to determine whether it might be possible to use this biocontrol method to provide quick knock-down control of germinable seeds. A sizeable fraction of the non-dormant seed bank is also killed by biocontrol treatments with this pathogen, suggesting that it may be possible to use this organism in place of herbicides, if highly effective strains can be found. Use of this biocontrol organism can potentially be incorporated into post-fire and restoration seeding projects in areas dominated by annual bromes, greatly improving chances of success. Our research project has three principal objectives: 1) Determine biocontrol efficacy against cheatgrass under realistic restoration scenarios in the field in terms of native grass emergence, establishment, and survival, 2) Systematically evaluate among-strain variation in virulence, growth rate, phytotoxin production, and environmental tolerance, and determine how these traits affect biocontrol efficacy, in order to select highly effective strains to use for biocontrol, and 3) Evaluate the potential effectiveness of this pathogen for control of other important annual grass weeds. For the field inoculation studies at former Wyoming big sagebrush sites in Utah, Idaho, and Washington, we will apply biocontrol treatments and plant native grass seeds on two dates in precision seeding studies, then follow establishment success across two years. For the strain trials, we will use techniques and procedures we have developed in our earlier studies to obtain pure cultures of pathogen strains from field-infected cheatgrass seeds, increase conidial inoculum of these strains, screen for virulence, growth rate, phytotoxin production, and environmental tolerance, and evaluate biocontrol efficacy in greenhouse and growth chamber bioassays. We will also obtain pathogen strains from five other important annual grass weeds: red brome, Japanese brome (B. arvensis), jointed goatgrass (Aegilops cylindrica), medusahead (Taeniatherum caput-medusae), and Africagrass (Ventenata dubia). All of these grasses are known hosts of the black fingers of death pathogen. We will test these strains in cross-inoculation trials to determine the level of susceptibility of these species to different pathogen strains and whether host-adapted strains would provide better biocontrol than strains specifically selected for use on cheatgrass.

Principal Investigator: Susan E. Meyer

Agency/Organization: Forest Service

Branch or Dept: RMRS-Shrub Sciences Laboratory


Other Project Collaborators

Type

Name

Agency/Organization

Branch or Dept

Agreements Contact

Susan T. Major

Forest Service

RMRS-Rocky Mountain Research Station

Budget Contact

Edith M. Cates

Forest Service

RMRS-Rocky Mountain Research Station

Co-Principal Investigator

Phil S. Allen

Brigham Young University

Department of Plant & Wildlife Sciences

Co-Principal Investigator

Julie Beckstead

Gonzaga University

Department of Biology

Funding Cooperator

Susan E. Meyer

Forest Service

RMRS-Shrub Sciences Laboratory


Project Locations

Consortium

Great Basin

Northwest


Level

State

Agency

Unit

STATE

UT

BLM

West Desert District

STATE

WA

FWS

Columbia National Wildlife Refuge

STATE

ID

BLM

Twin Falls District


Project Deliverables

There is no final report available for this project.
  ID Type Title
view or print   3562 Journal Article Plant Ecology
view or print   3563 Journal Article Journal of Natural Products
view or print   3564 Journal Article Tetrahedron
view or print   3565 Journal Article Journal of Agricultural and Food Chemistry
view or print   3429 Journal Article Invasive Plant Science and Management
view or print   3430 Journal Article Oecologia
view or print   3431 Journal Article Biocontrol Science and Technology
    3428 Journal Article Seed Science Research
    318 MS Thesis The Bromus tectorum-Pyrenophora semeniperda Pathosystem

Supporting Documents

There are no supporting documents available for this project.

Convert PDF documents to an html document using Adobe's online conversion tool.
Download Adobe Acrobat Reader