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 minimum but will often actually increase the 

 yield. Diseases which attack the foliage are controlled by spray- 

 ing 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 sea- 

 sons, and in wet sea- 

 sons at intervals of ten 

 to fourteen days as 

 long as the vines re- 

 main green. In a sea- 

 son of frequent rains 

 and moderate temper- 

 atures the omission of 

 any one of the appli- 

 cations may result in 



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

 United States Department of Agriculture. ) 



