PEACH DISEASES 



307 



of the normal number, so that the next year's crop of peaches 

 will be materially lightened. Young trees suffer severely; 

 when badly diseased, they become stunted and in some cases 

 are permanently injured. 



It should be stated that black-spot affects not only the fruit, 

 foliage and twigs of the peach, but also these same organs of 

 the apricot, nectarine and plum, making four prominent and 

 important stone-fruit trees in the category of hosts for the 

 black-spot pathogene. This fact adds to the economic aspect 

 of this disease. Of the peaches the Elberta is particularly 

 liable to extensive damage. Likewise the Champion, Carman, 

 Alton and others 

 are very suscep- 

 tible. 



Symptoms. 



The disease is 

 more likely to be 

 found on young 

 Elberta trees 

 than on peaches 

 of other ages and 

 varieties, al- 

 though practi- 

 cally all kinds are 

 affected to a vary- 

 ing degree. The 

 leaves (Fig. 81), 

 fruits and twigs 

 show symptoms 

 of the disease. 



On the leaves 



a shot-hole effect similar to the leaf-blight of plums and 

 cherries is produced (Fig. 81). The first evidence of the 

 trouble is a leaf-spot; hence the disease is at times called 



FIG. 81. Black-spot lesions on peaoh-leaves. 

 Note the shot-hole effect. 



