April 2001 // Volume 39 // Number 2 // Feature Articles // 2FEA2

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Public Education, Mapping, and Early Action to Control Russian Knapweed in Southeastern Arizona

Russian knapweed has been problematic in the Northern U.S. for decades, but only recently found in Southeastern Arizona. Due to its aggressive nature and threat to ecological and agricultural values, a working group was formed to address the problem. A plan of action was developed and implemented. The objectives of the project reported in this article were to: 1) develop a public outreach program to increase awareness of noxious weed impacts, 2) use GPS and GIS technology to map Russian knapweed infestations, and 3) use mapping data to plan and coordinate an integrated management strategy in Cochise County, Arizona. Due to these efforts, Russian knapweed infestations have been reduced and continue to be monitored and treated using an integrated management approach.

Kim H. McReynolds
Area Extension Agent, Natural Resources
The University of Arizona Cooperative Extension
Willcox, Arizona
Internet Address: kimm@ag.arizona.edu

Larry D. Howery
Range Management Specialist
School of Renewable Natural Resources
The University of Arizona
Tucson, Arizona
Internet Address: lhowery@ag.arizona.edu


Noxious weeds are non-native plant species capable of doing great harm to agriculture, navigation, fish, wildlife, and public health (Federal Noxious Weed Act 1975). The spread of noxious weeds has literally caused an ecological and economic disaster in some areas in the United States and Canada (Beck, 1993). Noxious weeds have detrimental effects on soil and water resources, reduce forage production for wildlife and livestock, reduce biodiversity, reduce land values, reduce net returns, and negatively impact local and regional economies (Olson, 1999). The Bureau of Land Management estimates that noxious weeds consume, on average, about 4,600 acres a day on Western wildlands (Rumburg, 1995). The annual cost of noxious weeds in the United States is estimated in excess of $20 billion a year (Cramer, 1995).

Russian knapweed (Acroptilon repens) is a perennial, exotic, cool-season dicot first introduced into the United States around 1898 from Eurasia (Whitson et al., 1992). It has since invaded over 1.4 million acres in the United States and Canada (Lacey & Olson, 1991). Russian knapweed has been problematic in the Northern United States for decades; however, a small infestation was recently reported in Southeastern Arizona in 1993, near the town of San Simon, Cochise County.

Cochise County is bordered on the east by New Mexico and on the south by the Republic of Mexico. It is approximately 80 miles square and contains 4,003,840 acres. Agriculture is a major contributor to the economy of the county. Cash receipts in 1995 from crops harvested in Cochise County were $39.2 million, and livestock were $18.5 million (Clark et al., 1997). The threat of Russian knapweed to the economic stability of Cochise County therefore has the potential for great impact. A recent Montana study estimated the economic cost of 3 knapweed species (spotted, diffuse, and Russian) exceeded $42 million on grazing (carrying capacity), wildlife habitat, and watershed capacity, which could support 518 jobs in Montana's economy (Olson, 1999).


The principal aim was to follow the cornerstones of weed management set forth by the Federal Interagency Committee (1998), including:

  • Public education and awareness,
  • Prevention and early detection,
  • Inventory and mapping,
  • Planning and coordination,
  • Application of integrated weed management practices (including mechanical, biological, cultural, and chemical methods), and
  • Monitoring and follow-up.

In 1996, the Arizona Department of Agriculture met with Cochise County Cooperative Extension concerning Russian knapweed infestations in Southeastern Arizona. This meeting initiated the formation of a working group to take action against the growing Russian knapweed problem in Cochise County.

The working group was comprised of representatives from the Arizona Department of Agriculture, The University of Arizona Cooperative Extension, Natural Resources Conservation Service, Arizona Department of Transportation, and National Park Service. These agencies and institutions are responsible for:

  • Regulation of noxious plants in Arizona,
  • Encouraging partnerships with public and private sectors,
  • Providing services to land owners for conserving, improving, and sustaining natural resources and the environment,
  • Managing vegetation along Arizona's state highway right-of-ways, and
  • Extending the benefits of natural and cultural resource preservation and outdoor recreation, respectively.

The working group's membership represented both public and private interests for noxious weed management in southeastern Arizona.

The primary objectives of the working group were to:

  1. Develop an educational public outreach program to increase awareness of noxious weed impacts,
  2. Use global positioning system and geographic information system technology to map Russian knapweed infestations, and
  3. Use mapping data to plan and coordinate an integrated management strategy for noxious weed infestations in Cochise County, Arizona.

To begin, the working group sponsored a "Noxious Weeds on Farms and Rangelands" workshop as one of the sessions offered at the annual Ag Day in Southeastern Arizona in February, 1997. This event brings together several hundred people who have direct and indirect interests in agriculture. The workshop was general in nature and covered the following topics:

  • What noxious weeds are,
  • Ecology of invasive species,
  • Five noxious weed species that threaten southeastern Arizona,
  • Ecological and economic impacts of noxious weeds, and
  • Integrated weed management.

The next step was to locate and map any additional populations of Russian knapweed beyond the infestation identified in 1993. Russian knapweed infestations were mapped in Cochise County while the plant was in full bloom, and therefore easier to detect, during July-August 1997. Cochise County was selected because there was an opportunity to eradicate or at least contain and control Russian knapweed due to its limited distribution reported in 1993. Also, there were no reports of populations of this weed in adjacent counties.

Observers were trained to operate hand-held global positioning systems and to identify Russian knapweed. They reconnoitered state, county, and city roads, searching for the weed. Russian knapweed coordinates were downloaded into the Arizona Department of Agriculture's geographic information system, which was used to generate a color map.

Following the mapping effort during the summer of 1997, we sent a letter and noxious weed literature to private landowners and farm and ranch managers in Cochise County who were on Cooperative Extension mailing lists. The letter explained why Russian knapweed and other noxious weeds are a concern in Arizona and extended an invitation to attend a second noxious weed workshop held during Ag Day in February 1998.

The purpose of the second workshop was to update landowners, farmers, ranchers, and the general public about the status of Russian knapweed and other noxious weeds in southeastern Arizona. Part of the workshop was an interactive session with participants to identify an integrated management strategy to address the Russian knapweed infestations detected by our mapping efforts.



Forty-five people attended the first noxious weed workshop in February of 1997. One hundred percent of participants found the workshop useful and stated that they had learned something at the workshop. Seventy-five percent said they learned "a lot" about the five species of noxious weeds that threaten Southeastern Arizona. Participants also stated that they increased their knowledge of the ecology of invasive species and integrated management options for the control of noxious weeds.

During the second workshop held in 1998, participants identified the following as priorities for future action:

  • Provide more educational opportunities to involve additional stakeholders,
  • Enhance cooperation with state, county, and federal agencies, and
  • Prioritize and manage noxious weeds across jurisdictional boundaries.

An important product of the 1998 workshop was a newspaper article that was published in two Cochise County newspapers. The article specifically addressed Russian knapweed as a local concern and encouraged people to become more aware of noxious weeds and their potential negative impacts.

Mapping and Management

We detected 77 Russian knapweed infestations in 1997 in addition to the original infestation reported near San Simon in 1993. Most of the infestations were in roadside right-of-ways, were less than 1 acre, and had not yet spread onto adjacent farmland or rangelands. It is unknown whether the 1997 infestations were already present in 1993, or if they had spread from the San Simon infestation. The small size of the majority of infestations detected suggested there was still an opportunity to effectively contain Russian knapweed infestations in Cochise County.

The map was made available to all working group participants and the interested public. It was also used by the Arizona Department of Transportation in 1998 to locate and treat Russian knapweed along state highways and county roads, using integrated weed management tactics such as selective herbicide application, and encouraging desirable plant growth and competition. The Arizona Department of Transportation incorporated the 1998 mapping data into their geographic information system and continues to monitor and treat Russian knapweed infestations within their jurisdiction as needed.

Implications and Conclusions

The spread of noxious weed infestations in the Western United States is often compared to an unwanted wildland fire (Dewey, 1997). Both wildfires and weed infestations start out small and spread relatively slowly. After a period of time, however, they begin to grow exponentially, and management becomes extremely difficult, if not impossible. One major difference between wildfires and weed infestations, however, is that with wildfires, the land often can recover. With weed infestations, on the other hand, the land is irreparably damaged. This is why public education, mapping, and early action are critical for controlling noxious weed infestations in the initial stages.

By acting early, when Russian knapweed populations were small in size, control efforts have been minimized in Cochise County, preventing large-scale problems. Monitoring of known population sites for seedlings and re-sprouts continues. Perennial weeds require perennial solutions. Cooperative Extension will continue to play a major role in offering public education programs on Russian knapweed and other noxious weeds that threaten Arizona.


Beck, K. G. (1993). How do weeds affect us all? In: An explosion in slow motion: noxious weeds and invasive alien plants on grazing lands. 8th Forum. Washington D. C.

Federal interagency committee for management of noxious and exotic weeds. (1998). Pulling together: A national strategy for management of invasive plants. 2nd edition. U. S. Government Printing Office. 22 pages.

Clark, L., Dunn, D, McReynolds, K., & Call, R. (1997). Cochise County Agriculture. Cochise County Cooperative Extension.

Cramer, G. C. (1995). Analysis of the implementation of noxious weed policy on Bureau of Land Management and Forest Service lands in Arizona. Ph.D. Dissertation. Univ. of Arizona.

Dewey, S. (1997). Noxious weeds: a biological wildfire raging out of control. Utah State University Cooperative Extension Service. 18-minute video tape.

Federal Noxious Weed Act (1975). Title 7 - Agriculture. Chapter 61 - Noxious weeds.

Lacey, J. R., & Olson, B. E. (1991). Environmental and economic impacts of noxious range weeds. In: Noxious range weeds. James, L. F., Evans, J. O., Ralphs, M. H., & Child, R. D., editors. Westview Press.

Olson, B. E. (1999). Impacts of noxious weeds on ecologic and economic systems. Pages 4-18 in Biology and Management of Noxious rangeland weeds. R. L. Sheley and J. K. Petroff (Eds.). Oregon State University Press, Corvallis.

Rumburg, B. (1995). The west grapples with weeds and livestock grazing. Society for Range Management Trailboss. September 1995.

Whitson, T. D., Burrill, L. C., Dewey, S. A., Cudney, D. W., Nelson, B. E., Lee, R. D., & Parker, R. (1992). Weeds of the west. The Western Society of Weed Science.


This project was supported by an Arizona Cooperative Extension Program Enhancement Grant. In addition to the authors, project members include: Everett L. Hall, Arizona Department of Agriculture (Retired); Clifton Taylor, Arizona Department of Transportation; Walt Saenger, National Park Service (Retired); and Dave Fisher, USDA Natural Resources Conservation Service.