EXPERIMENT STATION REPORTS. 



317 



The figures also show the failure which may come from using too 

 weak a solution. Two tablespoonfuls to 16 quarts of water uses formal- 

 dehyde at the rate of 1 pint to Gl gallons of water — far below the recom- 

 mended strength. 



The value of treatment year after year is indicated, as well as the 

 necessity of keeping on with the treatment in spite of a long history of 

 previous treatments. Chances of contamination from the few smutted 

 heads which do escape treatment, as well as the infestation which comes 

 from the separator make this necessary. 



RYE SMUT. 



Observation on Eye Smut {Urocystis occulta) was continued again 

 this year by Dr. Bessey. The following table gives a summar}^ of the 

 percentages of infection found: 



It would seem from these figures that rye smut is not as yet doing 

 great damage in the state, but that it may become serious enough to war- 

 rant treatment. Since infection occurs on the sprouting seed from 

 spores outside the grain, seed treatment with formaldehjde as recom- 

 mended for oats will be successful. It would seem advisable to begin 

 this as a precautionary measure. 



THE KELATION OF WEATHER TO EI»II)EMICS OF LATE BLIGHT 



OF POTATO. 



BY G. H. COONS. 

 (Abstract of address given at New York meeting of Botanical Society of America.) 



Study of the epidemics of Late Blight of potato in Michigan in 1912 

 and 1915 has indicated that there is a marked relation between weather 

 conditions in July and the severity of the disease. 



The percentage of loss in various parts of the state was determined 

 as accurately as possible by reports from potato buyers, county agents, 

 etc. Comparison of the map made from such data witli that showing 

 tlie rainfall for July shows striking correspondence. 



From cro]) reports and records of the station, it is loniid that the 

 epidemics of previous years Jiave come in those years when there was 

 more than an average rainfall in July. When such a July is followed 



