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Integrating Current and Emerging Herbicide Technologies in Leafy Spurge Control Programs

 Leon Wrage

Question 1. What major problem or issue is being resolved and how are you resolving it?

Leafy spurge is a serious economic problem in grassland; it is the most difficult of South Dakota's noxious weeds to control. Cost of herbicide inputs; environmental site limitations and effectiveness for eradication are factors that make integration of control options imperative . The use of reduced rates and multiple applications of existing technology and evaluation of new technologies will provide improved approaches for herbicides. This technology will be most effective when integrating with other biological and mechanical control practices.

Question 2. How serious is the problem? Why does it matter?

Historically, data reported shows leafy spurge has increased by 10% annually for the past 20 years. Current infestations in South Dakota pose a potential $10 million economic loss to production; and additional losses to wetland habitat, land value, and the potential cost to future generations if not controlled.

Question 3. How does it relate to the National Program(s) and National Program Component(s)?

The TEAM Leafy Spurge project is a part of the USDA/ARS Area-Wide Management Program. It is a component of Crop and Commodity Pest Biology, Control and Quarantine (304). TEAM Leafy Spurge complements efforts to develop new and improved pest control technologies and assess component technologies for integrated pest management (IPM) systems.

Question 4. What was your most significant accomplishment this past year?

Leafy spurge (Euphorbia esula) is reported to infest more than a quarter million acres in South Dakota; the current economic cost exceeds $10 million. This study in western, South Dakota will provide comparative performance data from current labeled herbicides including 2,4-D, picloram, dicamba, fosamine, and imazapic when used at reduced rates in a long-term test; evaluates reduced rates of herbicide in multiple application; evaluates rates and timing with repeated imazapic; identifies follow-up control programs; and using reduced rates of herbicides integrated with grazing. Producers in the project area have expressed that infestations on rangeland are now controlled and that efforts have halted the spread from existing infestations. Increased producer awareness through their participation in TEAM Leafy Spurge has increased their commitment and improved success from control efforts.

Question 5. Describe your major accomplishments over the life of the project, including their predicted or actual impact.

Data representing more arid conditions provides more accurate predictive results upon which producers can base selection of control programs.

Increased producer awareness through their participation in TEAM Leafy Spurge has increased their commitment and improved success from control efforts. Producers in the project area have expressed that infestations on rangeland are now controlled and that efforts have halted the spread from existing infestations.

Other anticipated long-term accomplishments include:
A. Contributions to technology that will sustain resources and productivity.
B. Development of a data base for improved recommendations for the region.
C. Increased adoption of an integrated pest management approach.

Question 6. What do you expect to accomplish year by year, over the next three years?

A. Collect year three weed control data from long-term treatments.
B. Evaluate forage response from multiple application.
C. Collect performance data for year one of follow-up treatment test.
D. Continue evaluation of grazing/low rate herbicide comparisons.
E. Utilize data collected at producer and agency training meetings.
F. Maintain long-term comparisons.
G. Collect year 2 data from follow-up test.
H. Develop follow-up herbicide program.
I. Long-term data collection
J. Terminate new technology study.
K. Prepare project summary.

Question 7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology?

Transfer of technology has been initiated to ranchers and agency personnel. The project has included a highly visible reporting and publicity. Tours, brochures, posters, and participation in planning and training meetings have been effective. Data has been presented in county and district training meetings.

Potential constraints for adoption of practices are partially dependent on weather. Fall conditions during the initial study period have been very dry; the current seasonal drought conditions will be a factor in performance and in ranchers' willingness to expend resources for control. Favorable livestock prices are an offsetting positive factor. The technology to evaluate reduced rates (reduced costs) with cost spread over multiple years will be an incentive to invest in control technology when limited resources are available.

Question 8. List your most important publications in the popular press (no abstracts) and presentations to non-scientific organizations, and articles written about your work (NOTE: this does not replace your peer-reviewed publications which are listed below).

Wrage, L., S. Clay, D. Deneke, and K. Nelson. 1998. TEAM Leafy Spurge Program. Poster display, TEAM Leafy Spurge, 2nd Annual Meeting, Rapid City, SD.

Wrage, L., and SD Weed and Pest Commission. 1999. Noxious Weeds. Extension Special Series 34. 26 pp.

Wrage, L., and D. Deneke. 1999. "Leafy Spurge Control and Plateau". Training session, Pierre, SD.

Wrage L., D. Deneke, and K. Nelson. 1999. TEAM Leafy Spurge Field Tour. Harding County.

Wrage, L. and D. Deneke. 1999. "Noxious Weed Data Report". Dept. publication. 43 pp.

Deneke, D. and L. Wrage. 1999. "Noxious Weed Update". Six district meetings for county and agency personnel. 200 participants.

Question 9. Scientific publications

None.

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