Il6 AGRICULTURE. 



CHAPTER XXIV. 



DISEASES OF THE ORCHARD. 



" An ounce of prevention is worth a pound of cure." 



FORMS OF DISEASE. The leaves and green twigs of all the 

 orchard trees are affected by diseases which are variously 

 named leaf blight, leaf curl, yellows, etc. On the branches of 

 plums and cherries we have black-knot. On the fruit we have 

 diseases called the spot, the scab, rust, etc. We know that 

 diseased fruit, such as spotted apples, is, as a rule, 

 stunted in size and distorted in shape, and is not so salable as 

 well-formed, clean fruit. Diseased fruit, also, will not keep so 

 long as perfect fruit. We do not, perhaps, realize that trees 

 whose roots, branches, or leaves are affected with disease will 

 not produce as large crops as perfectly sound trees. It is 

 especially important that the leaves be kept clean and thrifty. 



PREVENTION OF DISEASE. The first thing to be noted is 

 that all old fruit trees or bushes that are not bearing good crops 

 should be destroyed. When a tree becomes unfruitful it will 

 be neglected and then diseases as well as insects will find a 

 home in it. Even if at some distance from other trees, all 

 such should be cut down and burned, since the spores of these 

 diseases are very light and are carried long distances by the 

 wind and by insects. In the case of black-knot upon plums 

 or cherries, there is only one course to follow cut it off and 

 burn it. It will not do simply to cut it off and throw it on the 

 waste heap ; the spores will ripen there and spread to the other 

 trees. If affected twigs and limbs are cut off as soon as the 

 first signs of disease appear, we shall do much to stop the 

 spread of the disease. It may even be found to pay to cut 



