CHERRY DISEASES 



173 



enter the next season with decreased vitality. A case is on 

 record where 40,000 young cherry trees were lost on account 

 of leaf-blight alone. The loss in Ohio in 1905 is estimated at 

 $25,000. The preceding year it is estimated to have caused a 

 loss of 8 per cent, in Maryland. One nursery company in 



FIG. 48. Leaf-blight (yellow-leaf, or leaf-spot) on sweet cherry : types of 

 lesions on upper and lower surfaces. Center leaf shows whitish masses (spores) 

 of the pathogene. 



Nebraska claims to have lost $40,000 in 1903 on account of 

 this disease. These examples serve to show the possible destruc- 

 tion which may be wrought by leaf-blight. 



Symptoms. 



The fruit and pedicels are liable to show the disease, but the 

 foliage (Fig. 48) is by far the most common seat of the trouble. 

 Toward the last of May or early in June affected leaves exhibit 

 slightly discolored, dark-blue areas on the upper surface (Fig. 

 48, left). These are not more than one-eighth of an inch in 



