Crop Biosecurity
Prepared by
N. W. Schaad¹, J. J. Shaw², A. Vidaver³,
J. Leach⁴, and B.J. Erlick^5
1USDA ARS-Foreign Disease-Weed Science Unit, Ft. Detrick, MD 21702; ²Inst. Molecular Biology and Medicine, University of Scranton, Scranton, PA; ³University of Nebraska, Lincoln, NE 68583; ⁴Kansas State University, Manhattan, KS 66506; ⁵USDA ARS-Special Interagency Programs, Beltsville, MD 20705

Abstract
During the 7 - 11 August Joint American and Canadian Phytopathological Society meeting in Montreal, Canada, the American Phytopathological Society (APS) hosted a symposium entitled "Plant Pathology’s Role in Anti-Crop Bioterrorism and Food Security." Because of the interest in this topic, we are providing this APSnet feature article and discussion session as a platform for interested APS members and others to further discuss and develop ideas to help increase our nation’s crop biosecurity and food safety. Over the past several years there has been an increase in new and emerging plant diseases. Although these diseases are a likely result of natural causes, instances of deliberate introduction cannot be ruled out. We present references to several books, articles, and web sites which refer to anti-crop bioterrorism and biowarfare.

     The recent APS symposium on anti-crop bioterrorism   chaired by Dr. Anne Vidaver and sponsored by the Office of International Programs, Regulatory Plant Pathology, and Bacteriology committees was intended to better educate plant pathologists and the public about the potential of crop bioterrorism. In his keynote address, Dr. Tom Frazier stressed the need for government to address crop bioterrorism issues and for plant pathologists to assist in developing a science-based defense plan for crops (Dr. T. W. Frazier, "Bioterrorism and agriculture," see abstract). Several newspaper articles have been written about the APS symposium including: 1) Columbus Dispatch, (http://www.dispatch.com/news/newsfea99/sept99/bioterr.html); and 2) Calgary Herald, (www.calgaryherald.com:80/business/stories/990821/2754813.html). The Calgary Herald article entitled "Crop Warfare Combat Plan Urged" by Grant Robertson, provides a broad overview of the symposium.

     Because of the great importance and interest in the topic, this feature article has been prepared to provide a platform for interested members and others to further discuss and develop ideas for dealing with crop biosecurity issues. Numerous representatives of the administration and congress have publicly registered great concern regarding the threat of biological warfare (BW) to this country, especially manifested as bioterrorism. Most recently, in comments that were widely circulated in the press, Secretary of Defense William Cohen warned Americans of the likelihood of biological weapons attacks in the coming months and years (www.usembassy.ro/Documents/eur072699105.htm). One of the most important points made by the Secretary is that being prepared for an attack which may employ bioweapons of mass destruction is, by itself, a strong deterrent.

Availability of information on
anti-crop biological warfare (BW) in the public domain
     Although few books referencing BW matters mention anti-crop agents, recent articles and some internet web sites do refer to this subject. A special issue of Emerging Infectious Diseases published by the Centers For Disease Control and Prevention (Atlanta, GA), addressed a number of issues, including information-sharing (Kay et al., 1998), and bioterrorism and public health (Henderson, 1998; McDade and Franz, 1998). The current issue of Emerging Infectious Diseases (vol. 5, No. 4, 1999) is devoted to BW concerns. However, there is essentially no information concerning crop biosecurity.

     Some particularly useful examples of  available information on anti-crop BW include; 1) the web publication, The Battlefield of the Future (www.airpower.maxwell.af.mil/airchronicles/battle/bftoc.html) which provides a description of several scenarios in which a foreign country or even unscrupulous businessmen may wish to employ plant diseases for economic gain (Chapter 10, Biological Weapons for Waging Economic War); 2) a report by the Federation of American Scientists that was prepared by The Subgroup on Investigation of Alleged Use or Release of Biological or Toxin Weapons (http://www.FAS.org/bwc/report.html). This report covers a number of areas including ideas for strengthening current treaties and protocols. Appendix III discusses plant diseases and considerations for investigating a suspected occurrence of anti-crop warfare; 3) a NATO Advanced Research Workshop entitled "BTWC Security Implications of Human, Animal and Plant Epidemiology" which was held in the Cantacuzino Institute in Bucharest, Romania in June 1999. Major topics discussed at this workshop included the need for epidemiology and disease reporting and methods of outbreak investigation and analysis.  This and other related reports can be found at the University of Bradford, Department of Peace Studies site, http://www.brad.ac.uk/acad/sbtwc/; and  4) A microbiology course, taught by Professor R. E. Hurlbert, includes a chapter entitled "Biological Weapons; Malignant Biology" (www.wsu.edu/~hurlbert/pages/101biologicalweapons.html). While a comprehensive overview of the subject matter is presented, little is included about crops. A list of over 70 potential biological agents includes eight plant pathogens (four bacteria, three fungi, and one virus). This non-validated but provocative site is provided for information only.

    While not generally addressing plant diseases in the context of BW, the world wide web provides numerous resources of accurate and not-so-accurate information concerning general biological warfare and terrorism. As such, one should very carefully validate the sources and factual content of all data acquired through these resources. With this note of caution expressed, one of the most useful resources is Outbreak (www.outbreak.org/cgi-unreg/dynaserve.exe/index.html). Outbreak offers comprehensive and detailed online information about emerging diseases and has a large section on biological warfare issues that provides good background information, as well as many links.

    A list of plant pathogens that have been generally considered as potential anti-crop weapons can be compiled from several sources. One key source is the Australia Group. This informal group, comprising more than thirty nations including the U.S., was established in the 1980s to try to control the export of dual-use items and technology for chemical weapons by applying export licensing measures. In the 1990s controls for human, animal and plant pathogens and dual-use biological equipment were added. More than a dozen plant pathogens included for export control by the Australia Group are listed because of their harmful potential if transferred to nations with biological weapons programs or terrorists. An additional list of pathogens was provided by Weller et al. (1999) who discussed agents in the context of biological weapons and the problems that are posed for universities who wish to conduct research with organisms generally considered to be potential animal or plant weapons (Weller et al., 1999). Collectively, several plant pathogens believed to be suitable for weaponization are presented in Table 1. We assess that most of these pathogens have numerous deficiencies as bioterrorist or BW agents and, as such, may be inappropriate or too difficult to be used.

Table 1