Agroterrorism: An Assault on America’s Breadbasket

By: Megan Cahill, Anika Khan, and Marie Smithgall

Agriculture is a soft target for terrorism, and historical evidence indicates terrorists have considered attacks against our nation’s crops and livestock.  Current national and international agricultural models heavily utilize monocultures, fields with a single homogeneous crop grown extensively throughout an area.  However, if a monoculture’s cornerstone plant is susceptible to a particular plant pathogen, so too are all of the plants in the field.   The widespread use of monocultures correlates to a decreased resistance to pathogens that originate either from a natural epidemic or a terrorist attack.  Increased use of seed mixtures would provide a reduction in the severity and spread of a terrorist attack, and would serve to deter future attacks since terrorist organizations such as Al-Qaeda prefer attack plans with high potential for success. Seed mixtures are increasingly being used globally for their various benefits.  A policy that further encourages their use would further stabilize the economy and bolster national security.

Although not a traditional act of terrorism, agroterrorism actions are the “deliberate introduction of an animal or plant disease with the goal of generating fear, causing economic losses and/or undermining stability.”1 The far-reaching economic and public fear effects, as evident in previous agriculture crises such as the 1970 American Corn Blight, clearly classify agroterrorism as a form of terrorism.2 At a 2003 congressional hearing, Senator Susan Collins of Maine recognized the potential impact of agroterrorism in saying, “In the war on terrorism, the fields and pastures of America’s farmland might seem at first to have nothing in common with the towers of the World Trade Center or our busy seaports. In fact, however, they are merely different manifestations of the same high-priority target, the American economy.”3

Agroterrorism presents an urgent issue.  There are eight nations with either current or past biological and toxin weapons (BTW) programs, and non-state actors have the potential to utilize bioterrorism for their cause.  Evidence found in caves in Afghanistan suggests that Islamic militants have an interest in the weaponization of wheat rust.4

The appeal of agroterrorism is that it is low-tech but high-impact.  For example, only 3 grams of a rice blast fungus per hectare could infect 50-90% of crops exposed.5 In addition, the physical resources necessary to produce such an agent including laboratory equipment, and dispersal mechanisms are easily available to anyone in the scientific, pharmaceutical or agricultural business communities. The required knowledge base is also very low.  Many agroterrorism agents can be made in high school labs within a few hours or days, and with the advent of the Internet, all of this information is easily accessible online.6

Agriculture is termed a “soft target” because of its low level of security.7 Most fields and pastures are unprotected and unsupervised at night.  Furthermore, most crops now exist as monocultures; thus, they all share the same vulnerability to a pathogen and the entire harvest can be lost to disease.8 The threat has been documented in the past, such as the interest of the September 11, 2001 terrorists in the procurement and characteristics of crop dusters.9 Counterterrorism experts have suggested the reason that an attack on the food supply has yet to occur is because such an attack would lack a central image for the media upon which to focus.10 However, agriculture is a valuable part of our economy, and an agroterrorism attack would result in a disruption of American and international trade, economic loss, an increase in public fear, and potentially the loss of human life.

There would be significant economic loss if the wheat rust Ug99, which is currently plaguing the African continent and Arabian Peninsula, spread to the United States.  The Department of Agriculture has estimated 40 million acres of wheat in the United States is susceptible and that the economic loss could exceed 10 billion dollars.11 As an example, Kansas, the largest wheat producing state, is predominantly composed of monocultures.12 Two central Kansas counties, Rush and Barton, have 281,716 acres of wheat.13 In a hypothetical agroterrorism attack, terrorists could procure black stem rust fungus from overseas and then culture the fungus in a rudimentary laboratory here in the United States.   Two crop dusters could cover the combined farmland of Rush and Barton counties in two passes over six hours.14 Since the attack could occur in one night in these scarcely populated counties, the flights could occur without interruption.  Captured documents indicate that Al-Qaeda leadership will only approve on-the-ground attacks if they have a success rate of 75-100% destruction.15 Ug99’s high rates of infection and virulence, 80-100%, places an agroterrorism attack well within the operations criteria for Al-Qaeda.

Based on wind trajectories and the previous spread of wheat funguses in the United States, this pathogen would be expected to move 200-300 miles per week.16 In the above scenario, the introduced wheat fungus would expand radially out from Kansas along the swath of wheat fields in the central United States.  Each week as the fungus continues to infect more plants and the number of spores it is producing exponentially increases, the pathogen would gain a foothold in monoculture wheat fields due to their lack of genetic diversity and complete susceptibility to infection.  After four weeks, the fungus would likely be found from Texas to North Dakota and even extend into Canada.  Thus, a terrorist attack involving black stem rust fungus or a similar pathogen is plausible and dangerous.

Cultivar mixtures demonstrate positive benefits in two key areas: disease control and overall yield.  Studies show that on average, yield increase was found to be 10.1% in cultivar mixtures, compared to monoculture mixtures, in the presence of stripe rust.  In addition, a 2.5% increase occurred in the absence of any type of disease.17 Under leaf rust conditions, cultivar mixtures with 2 components showed a 37% disease reduction rate, while mixtures with 5 components produced a rate of 70%.  Disease reduction due to mixing improved as the number of cultivars in the mixture increased.  Ultimately, the integration of cultivar mixtures into American farming will create a platform for risk reduction.

Cultivar mixtures are a practical, long-term solution to mitigate the threat of pathogens released by terrorists.  A policy that further encourages their use would further stabilize the economy and bolster national security.


  1. Jim Miller, “Agroterrorism: Threats and Preparedness”, (CRS Report for Congress, 2004)
  2. Bauer, Marvin E., “The Corn Blight Problem–1970 and 1971” (LARS Technical Reports, 1972)
  3. Susan Collins, “Agroterrorism: The Threat to America’s Breadbasket”, (Hearing before the Committee on Governmental Affairs, United States Senate, November 19, 2003)
  4. J. Fletcher et al, “Plant Pathogen Forensics: Capabilities, Needs, and Recommendations”, (Microbiology and Molecular Reviews, 70:2:450-471, 2006)
  5. Bailey, Katherine, “The Biological and Toxin Weapons Threat to the United States.” (National Institute for Public Policy, 2001), p. 6
  6. Bailey, p. 4
  7. Bailey, p. 2
  8. S. Cupp, D. Walker, J. Hillison, “Agroterrorism in the US: Key Security Challenges in the 21st Century”, (Biosecurity and Bioterrorism: Biodefense Strategy, Practice and Science, 2004)
  9. Bailey, p. 12
  10. RAND, Agroterroism: What is the Threat and What Can Be Done About it?”, (RAND Research Brief, 2003)
  11. B. Koerner, “Red Menace: Stop the Ug99 Fungus Before Its Spores Bring Starvation,” (, 2010)
  12. Kansas Department of Agriculture, “Kansas Agriculture Statistics”, (, 2006)
  13. Kansas Geological Survey, “Geohyrdology of Rush County”, (Kansas University, 2008)
  14. Thrush Aircraft, “Aircraft”, (2011)
  15. M. Horowitz, “Non-State Actors and the Diffusion of Innovations: The Case of Suicide Terrorism,” (University of Pennsylvania, 2009)
  16. USDA Cereal Disease Laboratory, “Cereal Rust Bulletin”, (USDA, 2011)
  17. Mundt, “Use of Host Genetic Diversity to Control Cereal Diseases: Implications for Rice Blast.” Rice Blast Disease (293-308, 1994)
  18. Image credit (public domain): Groth, Donald. “Rice blast symptoms.” Wikimedia Commons. Last modified March 16, 2009.
  19. Image credit (public domain): USDA. “Wheat harvest.” Wikimedia Commons. Last modified December 2004.

Megan Cahill, Anika Khan, and Marie Smithgall are undergraduate students at Georgetown University. Follow The Triple Helix Online on Twitter and join us on Facebook.