59 



and the exposed wood, when dry, waxed over or shaded. Such 

 places should be covered with wax, but to do everything when it 

 should be done, and how it should be done in an orchard is not 

 always possible ; cut out the gum at all events, as that if done in 

 time will save the tree. 



With the plum and prune this disease develops somewhat 

 different symptoms, aud is more difficult to control because less 

 apparent to the inexperienced grower, and many grown gray in 

 the service wonder why their trees die. A dark, " dead " appear- 

 ance of the bark, often forming a slight depression, and if the tree 

 be moderately vigorous a cracking of the bark, and also exudation 

 of gum, are all symptoms, which, either one or all, require prompt 

 treatment. This treatment is simply to cut out all dead or dis- 

 eased bark, which should be done cleanly and neatly, and wax or 

 paint the exposed wood. 



If the tree is too far gone to be saved, it may be sawn off at or 

 below the ground, and grafted. Scions should be kept dormant 

 for such an emergency, so that it could be done as late as Septem- 

 ber. This disease is not of the root, which invariably remains 

 healthy until after the whole top is dead, and may continue still 

 to live, by throwing up suckers. 



This very prevalent disease is often called u sour-sap," which 

 means even less than " malaria " in the human family, being 

 capable of so wide an interpretation. It is not caused by wet 

 land, and has nothing to do with the root, but it is most probably 

 due to a sudden chilling or freezing of the sap on the most 

 exposed side in the spring, after a period of warm weather has 

 started growth. This causes a rupture of cells, decay of tissue, 

 fermentation of sap, and death. To prevent such a catastrophe, 

 keep the trees protected while young, from the time they are 

 planted by wrapping with burlap, or watch them every spring 

 from the first, and cut out any decayed or discoloured spot while 

 small. It is commonly supposed that trees thus affected die very 

 suddenly. They appear to do so, it is true, one day being in 

 bloom, or in leaf, and in forty-eight hours, or less, dead. In 

 reality such death is lingering, the condition above described 

 causing a gradual decay which does not terminate fatally until it 

 has spread all round the tree. 



With the cherry the disease acts more rapidly than with the 

 prune or plum, and while in this case it may be a specific com- 

 plaint due to other causes, I am firmly convinced it is largely due 

 to climatic influences." 



