COMMON POTATO DISEASES AND THEIR CONTEOL. 



A. VINCENT OSMUN, AMHERST, MASSACHUSETTS. 



The potato is subject to some of the most destructive diseases 

 affecting cultivated crops, and the losses are often very heavy. 

 There are, however, 

 definite and effective 

 control measures for 

 most of these diseases, 

 and proper attention 

 to them will not only 

 reduce losses to a min- 

 imum but will often 

 actually increase the 

 yield. Diseases which 

 attack the foliage are 

 controlled by spraying 

 with fungicides; for 

 those which work on 

 the tubers and stems 

 other control measures 

 must be applied. 



The effectiveness of 

 spraying potatoes de- 

 pends on keeping the 

 vines thoroughly cov- 

 ered with the spray 

 material throughout 

 the growing season. 

 This is accomplished 

 only by spraying at 

 least three or four times in ordinary seasons, and in wet 

 seasons at intervals of ten to fourteen days as long as the 

 vines remain green. In a season of frequent rains and moder- 



FiQ. 1. — Early blight. (After Farmers' Bulletin No. 91, 

 United States Department of Agriculture.) 



