54 MANUAL OF FRUIT DISEASES 



protect a fresh injury or decay in its early stages. It often 

 necessitates the expenditure of a great deal of time and money 

 to treat properly the same injury after it has been neglected for 

 a few years. 



The cutting-out of cankers is a method to be employed when 

 the orchardist is satisfied that the value of the limb warrants it. 

 An attempt to remove all kinds and sizes of cankers from an 

 infested orchard, without regarding the value of the limbs, is 

 likely to result in discouragement with the whole matter. 

 Such, practice is neither good nor profitable. The grower's 

 judgment must guide him. 



Certain tools have been found advantageous for this work. 

 A draw-shave for use in removing diseased bark, and a farrier's 

 knife for trimming the margin of the wound, are the chief tools 

 needed. The knife must be sharp, for a dull edge may injure 

 the growing part. The pruner should not wear heavy leather- 

 soled shoes, since canker fungi may get into the bark through 

 wounds caused by such shoes. It is suggested that rubber 

 boots, or some type of soft-soled shoes, be worn in connection 

 with such operations. 



In treating cankers it is necessary to determine the limits of 

 the diseased tissue. This may be done by examining the canker 

 externally or by shaving off bits of bark until the line of discol- 

 oration is located. The depth of the cut depends on the depth 

 of any indication of disease, that is, discoloration. If the canker 

 is for the most part superficial, penetrating the wood only in 

 spots, the bark may be removed as described above, the deeper 

 spots being rimmed out with a farrier's knife. If the fungus 

 has entered the wood, either locally or in long streaks, the dis- 

 colored part must be removed. If the streak extends for a 

 considerable distance, the case may warrant the removal of the 

 whole limb. So far as possible the wound when finally shaped 

 should be pointed above and below, as this facilitates healing ; 

 if the cut is left in a rectangular form, the upper and lower 



