STREET AND HIGHWAY PLA X 1 1 \( ;. 107 



and absorb directly. This, of course, results in the starvation of the 

 tree, and often various substances are given off by the fungus in its 

 assimilation processes, which lead to the actual disintegration ot the 

 woody tissues and their subsequent decay. 



The control of fungous diseases must be by preventive measures. 

 Care should be taken that all wounds should be dressed immediately 

 and the trees should be kept in a healthy condition. 



Fungicides are of value in checking the spread of diseases by spread- 

 ing a thin film of the material over the susceptible surfaces of the plant 

 so that spores falling on it will be killed or the germinating hyna- 

 will be killed. These preparations are usually solutions of copper salts. 

 Bordeaux mixture : 



4 pounds copper sulphate. 



4 pounds fresh lime. 

 50 gallons water. 



Ammoniacal copper carbonate : 



5 ounces copper carbonate. 

 3 pints ammonia (strong) . 

 50 gallons water. 



Often fungous diseases are' found in connection with old wounds 

 which have arisen in various ways, as breakage from wind and snow, 

 improper pruning, or the lack of dressing on the cuts after pruning. 

 The matter of proper dressing for wounds has been discussed, but it 

 may be well to note at this point some of the ways in which old injuries 

 may be repaired in some degree. 



Slight wounds, as the abrasion of the bark, should not be neglected. 

 Carefully cut away all the bark which is loosened from the wood, leaving 

 a smooth edge, and paint the exposed wood with coal tar to prevent its 

 drying out and to prevent the entrance of insects and fungus spores. 



Large wounds should be treated correspondingly if they are fresh and 

 upon the surface. If they are old wounds and have become cavities 

 extending far into the trunk of the tree, they require more complicated 

 treatment. This is especially true if fungous diseases have been at 

 work. There are times when it is not worth while to repair such trees, 

 but often valuable specimens may be saved by heroic treatment. 



In repairing a cavity all the decayed and diseased wood must be 

 removed, so that a surface of healthy tissue will be exposed. This 

 surface is washed with an antiseptic solution and covered with molten 

 coal tar. The cavity is then ready for filling. The manner of filling 

 will vary slightly according to the size of the cavity. If the cavity is 

 small, it will probably retain the filling, providing the cavity is larger 

 than the opening into the cavity. This will prevent the filling from 

 working loose and falling out. If the cavity is very shallow an extra 



