Pruning saws, shears and other pruning tools can spread disease organisms from one tree to another or from one part of a tree to another part of the same tree if not properly disinfected.

The 1991 U.S. Department of Agriculture bulletin on Fire Blight (page 64) states "if pruning is done during the dormant period, it is advisable to disinfect tools. However, if fire blight pruning is done any other time, pruning tools must be disinfected between each cut". Harris (page 405) indicates when pruning infected limbs, tools should be disinfected before pruning the next tree to avoid the spread of the disease.

Recommended disinfectants:

• denatured methyl alcohol - (shellac thinner)
  
• 10% sodium hypochlorite (i.e. bleach) solution - can be quite corrosive on pruning equipment. Use with care!
  
• a general purpose household disinfectant such as Lysol

References used:

• Bilerbock, T.E., R.E. Bir & M.A.Paul. 1993. Pruning Field Grown Shade & Flower Trees.
• Harris, Richard W. 1992. Arboriculture: Integrated managment of Landscape Trees, Shrubs, and Vines. Second Edition. Regents/Prentice Hall
  
• Horst, R. Kenneth. 1979. Westcott's Plant Disease Handbook: Fourth Edition. Van Nostrand Reinhold Company, New York
  
• van der Zwet, T., and S.V. Beer. 1991. Fire Blight - Its Nature, Prevention, and Control: A Practical Guide to Intergrated Disease Management, U.S. Department of Agriculture, Agriculture Information Bulletin No. 631, 83 pp.