176 



Bulletin 131. 



and again as soon as the leaves are off in the fall. If trees are 

 thoroughly sprayed every year with Bordeaux mixture for the 

 leaf-blight fungus, the black-knot will make comparatively few 

 inroads into the orchard. 



The blight which causes the leaves to fall in August or Septem- 

 ber is one of the most serious diseases of the plum orchard ; but 

 the disease can readily be kept in check by thorough spraying 

 with Bordeaux mixture two or three times during the summer. 



We have found, at Ithaca 

 that we can hold the leaves 

 on until frost by sprayings 

 which have begun about 

 two weeks after the blos- 

 soms fall, and repeated two 

 or three times during the 

 season. A somewhat full 

 account of these experi- 

 ments will be found in our 

 Bulletin 86. 



The fruit-rot is another 

 serious difficulty of the 

 plum. This is the work of 

 a fungus. Many times the 

 dead and dried fruit may be 

 seen hanging upon the tree 

 all winter, as shown in Fig. 

 38 ; and in such cases it is 

 very likely that the fruit- 

 spur will be killed as the up- 

 per one in the picture has 

 been. In handlmg this disease, the first consideration is the fact 

 that some varieties are much more susceptible to it than others 

 are. The I^ombard is one of the very worst. Again, if the fruit 

 grows in dense clusters, the disease is more apt to be severe. 

 The thinning of the fruit, therefore, is one of the very best preven- 

 tives of the spread of the disease and at the same time, also, one 

 of the most efficient means of increasing the size, qualit}' and sala- 

 bleness of the product. It may, therefore, be expected to pay in 



}fi,'— Fruit-rot of the plum. The upper 

 spur is dead, probably killed by the 

 fungus. 



