I04 



NOTES ON APPLE AND POTATO DISEASES 



Fig. 37. — Germinating Spores of Early Blight. Magnified. 



From these not wholly concordant results we prefer rather 

 to point out indications than to draw final conclusions. 



The indications are that, first, all of the fertilizers named 

 may favor the development of the scab to a greater or less de- 

 gree ; hence as fertilizers cannot be dispensed with, the greater 

 advisability of treating- the seed. Second, air-slaked lime, 

 plaster, and ashes are especially likely to increase the amount 

 of scab. 



POTATO BLIGHTS OR " RUSTS " 



As indicated above there are two forms of ''^ blight ''"' or 

 " rust^^'' the early ?^w^ the late. There is usually little difiiculty 

 in distinguishing between the two. The early blight appears 

 in June or July, the late in August. The early blight presents 

 numerous sharph^-outlined, dark brown spots on the leaves ; 

 the late blight manifests itself as a progressive withering or 

 dying of the leaves, spreads more rapidly than the early ^ and 

 usually presents a readily seen white mold-like growth on the 

 under side of the leaves. Both diseases often appear together, 

 especially on late varieties. Both of these diseases are spread 



