MICHIGAN ACADEMY (W SCIENCE. 285 



tubers, where formed, soon rotted in the ground. In some oases, where the 

 plants were not entirely killed, while still prostrate, they began to revive at 

 the tip, and this portion would become erect and develop in a normal way. 



Although the above observations do not in all cases show a correlation 

 between weather and the prevalence of the disease, as for example, the distri- 

 bution of Black Leg, there were some quite evident correlations observed. 

 Early Blight was evident almost exclusively in the upper peninsula, wIumc 

 there was plenty of moisture. The fact that Michigan did not have a cool, 

 wet July, followed by an August with moderate or heavy rainfall, and that 

 there was no epidemic of Late Blight, is further proof that the relation 

 between weather and Late Blight suggested by G. H. Coons * holds true. 

 Fusarium AVilt showed no relation to weather, but rather was related to soil. 

 and general cultural conditions. Based upon my observations, I can make 

 out no connection between the occurrence and severity of Tip Burn and tlie 

 different climatic regions of the state. This, however, is a trouble to which 

 great attention should be given, regardless of whether Tip Burn is a stig- 

 monose or a disease caused by a pathogene transferred by the Leaf Hopper. 



Unsatisfactory and incomplete as the results of the survey were, the obser- 

 vations have already proved to be of such value as indicating further research 

 that it seems highly desirable to continue work aldiig this line. i)erhaps on 

 other crops as well, in suctooding yo:irs. 

 Michigan Agricultural College. 



♦Special Bulletin 85. Michigan Agriculluial Ccilicye Kxijcrinicnt Slatinn. 



