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 
