Cfhe Connecticut Tlgricultural ‘Experiment Station 
123 HUNTINGTON STREET BOX 11C6 NEW HAVEN, CONN. 06504 fbWxaxJffW* 
(203) 789-7258 
Founded 1875 
Putting science to work for society 
26 January 1978 
Dr. Dewitt Stetten, Jr. 
Deputy Director for Science 
Office of the Director 
National Institutes of Health 
Bethesda, MD 20014 
Dear Dr. Stetten: 
Several plant scientists have recently approached us concerning hazard 
assessment of plant pathogens as they pertain to the revised Guidelines. For 
shotgun experiments, all prokaryotic plant pathogens are lumped with Class 2 
animal pathogens necessitating a P3 + EK2 categorization. This is certainly 
arbitrary and could be unnecessarily restrictive for many plant pathogens. 
Moreover, all plant virus DNAs as vectors are classified P3. In view of the 
fastidious requirements for transmission of DNA plant viruses and the lack 
of evidence suggesting they are a serious danger we think P3 is also unneces- 
sarily restrictive. 
Dr. C. I. Kado and three of his colleagues at Davis (in a letter to the 
Director, dated 12/5/77) have suggested a scheme for hazard classification of 
bacterial plant pathogens. This scheme could be a starting point for a dis- 
cussion of the hazard classification of all types of plant pathogens, not just 
bacteria. We think the time has come for us to face this issue, as hazard 
assessment will certainly enter into the use of recombinant DNA with plants 
and their pathogens. We are not entirely convinced that we can devise a 
meaningful scheme but think we should try. If this is in order we would like 
The Recombinant DMA Committee at its next meeting to consider providing 
sponsorship for a group of concerned plane scientists to consider these issues. 
With best wishes. 
Yours sincerely. 
Peter R. Day, Head 
Department of Genetics 
PRD/ebb 
cc: Dr. C. I. Kado 
P&b. 'Uh. 
Dr. Herman Lewis 
Milton Zaitlin 
Professor 
[Appendix A — 226] 
