Indiana Plant Diseases, 1921 



185 



the yield about 40 per cent and must be recognized as an extremely 

 important loss-producing factor in this state. The desirability of ob- 

 taining seed potatoes free from leaf-roll and mosaic is perfectly obvious. 

 In the late crop, early blight, caused by Altemaria solani, was 

 exceptionally prevalent this season. Gaylord reported that it was worse 

 in the late crop than he had ever noted in his experience and records 

 its presence in 12 counties. Gregory reported that early blight was 

 epidemic in Floyd and Harrison counties. In some fields the disease 

 appeared to be responsible for the yellowing and premature death of 



Fig. 8. Potato diseases. A and B. Effect of Rhizoctonia on sprouts. 

 stage of black leg caused by Bacillus phijtophthorus. 



C. Advanced 



many plants. Early blight was prevalent during the entire season in 

 fields under observation near Lafayette and Hammond. 



Gregory found one tuber from the 1920 crop of a grower near 

 New Albany which was affected with late blight rot, due to Phytophthora 

 infestans. This is apparently the first specimen record of this dis- 

 ease for the state. Gregory was unable to find any trace of the disease 

 in the 1921 crop on the same farm. Although the extremely wet weather 

 of August and September should have favored the occurrence of late 

 blight, it was not found in any of the numerous fields examined. On 

 the older stems of the early crop, sunken lesions located just below the 

 points of attachment of the leaves were found very abundant. With 

 these lesions, a fungus of the Gloeosporium type was commonly asso- 



