18 



ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 50 



Fijj- 19- — This section of a tree shows the drain hole bored at the proper 

 angle and to the proper depth to insure effective drainage and the drain pipe 

 so inserted that it does not penetrate diseased wood (discolored wood indi- 

 cated by arrows) and interfere with drainage of the sap that accumulates. 



Precautions 



Precautions should be taken to prevent spreading of wet- 

 wood bacteria from diseased to healthy trees. Although wetwood 

 appears to be present in most elms, it occurs only occasionally in 

 most other kinds of trees. Tools used in pruning elms should be 

 treated with a disinfectant to prevent their spreading bacteria to 

 other branches or trees. Denatured alcohol, used as a spray or 

 dip, is a satisfactory disinfectant. 



Cures 



Even the most effective sap and gas drainage will not cure 

 a tree of wetwood. It will only alleviate the situation by prevent- 

 ing fluxing through wounds. 



