WCC77: Biology and Control of Winter Annual Grass Weeds in Winter Wheat
(Multistate Research Coordinating Committee and Information Exchange Group)
Status: Inactive/Terminating
WCC77: Biology and Control of Winter Annual Grass Weeds in Winter Wheat
Duration: 10/01/1999 to 09/30/2004
Administrative Advisor(s):
NIFA Reps:
Non-Technical Summary
Statement of Issues and Justification
Good progress has occurred regarding the management and control of winter annual grass (WAG) weeds, particularly jointed goatgrass (Aegilops cylindrica) and downy brome (Bromus tectorum) in winter wheat. Much of the credit must go to regional efforts coordinated by the WCC-77 project. Downy brome and jointed goatgrass remain the two most threatening grassy weeds in the winter wheat producing areas of the United States, but cheat (Bromus secalinus), ripgut brome (Bromus diandrus), Italian ryegrass (Lolium multiflorum), and feral rye (Secale cereale), pose smaller but important economic threats to winter wheat. The combined infestation of these six WAG weeds remains at more than 20 million acres in winter wheat and continues to threaten the stability of winter wheat production in the Western United States. They cause winter wheat yield losses of approximately 10 percent for a combined annual crop loss of one-half billion dollars. Farmers in areas of heaviest WAG infestation suffer total winter wheat loss and are prevented from using winter wheat as a cropping option in some locations. WAG weeds are increasing because of increased use of reduced- or no-tillage farming, low competition and semi-dwarf wheats, highly effective broadleaf control herbicides, and few selective grass selective herbicides.
Jointed goatgrass infests about 5 million acres of wheat land from the Great Plains to the Pacific Northwest and is spreading. Direct and indirect losses from jointed goatgrass exceed $145 million annually. Winter annual brome species infest up to 15 million acres, feral rye infests about 1 million acres, and Italian ryegrass infests up to 0.5 million acres in the western U.S. Management of WAG species is challenging because infestation levels and weed competitiveness with winter wheat vary from year to year depending on environmental conditions and time of emergence relative to wheat, high herbicide costs, poor or inconsistent herbicidal control and/or marginal selectivity, and existence of resistant weed biotypes. In many locations, Italian ryegrass biotypes are resistant to the most effective herbicides available. Rotation to summer annual crops and tillage are the only jointed goatgrass management practices available because selective herbicides to control this weed in winter cereals are not available at the farm level.
Tillage has been used successfully for WAG control during non-crop periods, but tillage destroys protective crop residues and increases the potential for soil erosion. Conservation tillage systems designed to reduce soil erosion often use herbicides to replace tillage for part of the weed control program. WAG weeds are well adapted to conservation tillage systems. Several herbicides labeled for selective control of WAG in winter wheat require tillage for incorporation, thus their use is limited in conservation systems. Also, growers increasingly are reluctant to apply preemergence herbicides because they want to assess the need and estimate economic impact before deciding to apply a herbicide. However, selective postemergence herbicides are either nonexistent or few in number depending on the targeted species.
Objectives
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Broaden the scientific discipline base to discover the ecology, biology and economic thresholds of annual grassy weeds in cereals and to formulate sustainable integrated management programs for those species in winter wheat. A multi-strategy approach is emphasized to incorporate improvements as new techniques appear.
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Integrate recently discovered selective herbicides for annual grass weeds in cereals into a balanced integrated approach to reduce or eliminate development of herbicide resistance in winter annual grasses. Incorporate herbicide resistant cereal crops in the program where appropriate.
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Coordinate research and technology transfer efforts initiated and funded by the Jointed Goatgrass Research Initiative and other sources and disseminate research findings on jointed goatgrass management to producers in appropriate formats. Research priorities for the National Jointed Goatgrass Research Program-2000 include: A. Integrated management: Combine individual practices into systems that will minimize weed impact, be profitable, and environmentally sustainable B. Technology transfer: Develop materials to increase awareness and communicate prevention and management strategies C. Management of herbicide resistant wheat: Continue to determine the potential benefits and problems of resistant wheats and how they can be integrated into the management system D. Seed dormancy and longevity: Perform studies on seed dormancy to determine how cultural control practices could be enhanced E. Bioeconomic modeling: Determine economic thresholds for wheat yield and quality losses.
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Develop a reference library on winter annual grass species and a home page on the World Wide Web to facilitate information sharing and technology transfer related to winter annual grass weeds.
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Procedures and Activities
Expected Outcomes and Impacts
- outcomes The communication and coordination fostered by this project will allow rapid assessment of control measures over wide geographic areas, hasten the development of regionally adjusted bioeconomic models and profitable, socially-acceptable farming practices to manage and reduce the impact of WAG weeds. The reference library will be a repository for all known publications on relevant WAG weeds. Communication and sharing the most current information among WCC-77 participants will greatly aid technology transfer via extension education programs in each state. Information often is useful beyond the state where it was generated when it is adapted to a state's specific cropping systems or environment.
Projected Participation
View Appendix E: ParticipationEducational Plan
ed_plan
Current information on the biology and management of WAG species will be transferred to research and extension personnel, crop advisors/consultants, and growers in each state through informational meetings, field tours, research and extension publications, radio and television interviews, and popular print media. Research findings will be presented and published in research reports and/or proceedings of regional and national weed science societies, as theses or dissertations, and/or referred journal publications. A regional educational publication on jointed goatgrass will be prepared and a symposium on jointed goatgrass will be conducted at an annual meeting of the National Association of Wheat Growers.
Organization/Governance
governance
"Chair: 1. Maintain a liaison with the Administrative Advisor, CSREES Advisor, and other organizations with related interests. 2. Arrange for the annual meeting (room, overhead/slide projector, etc.) at site chosen by the membership. 3. Solicit items of business, prepare agenda, and preside at the annual meeting. 4. Appoint subcommittees as necessary to carry out WCC-77 business.
Recording Secretary: Record and submit minutes of the annual meeting to the Administrative Advisor and member participants.
Subcommittees: No standing subcommittees. Appointed as necessary by the chair."
Literature Cited