MICHIGAN ACADEMY OF SCIENCE. 



233 



facts necessarily gave an extremely large copper sulphate coefficient. 

 For example^, tlie coefficient given by Bowker's product with G. rufo- 

 maculans as the test organism^ was 29.2^ whereas with E. parasitica tlie 

 same mixture gave a coefficient of 160. In reality the difference is even 

 greater than the figures indicate for the copper sulphate standard in the 

 first M'as a 10% solution while in the second a 20% solution was used. 



As would be expected tliere was no such discrepancy exhibited when 

 E. parasitica was used as the test organism with tlie copper fungicides. 

 Table No. 6 shows the results with the two copper compounds using a 

 20% copper sulphate solution as a standard. 



Table No. 6. 



Temperature of exposure, 18°-21° C. 



Cultures, Endothia })arasitica on potato agar. 



Age of Cultures, 8-10 days. 



Amount of spore suspension and fungicide per plate, 0.2 cc. 



Amount of potato agar per plate, 10 cc. 



Temperature of incubation, 28° C. for eight days. 



X=growth. 



0==no growth. 



Fungicide. 



Bowker 

 Chemical Co. 

 I,. S. 

 (III. 1-10 



Time of 

 exposure 

 (in min.) 1-300 



5 

 If) 



I:) 



O 



() 

 () 

 () 



I-S50 

 X 



o 

 () 

 () 



Dilutions. 

 1-100 1-150 1-500 



X 

 X 



o 

 () 



X 

 X 

 X 

 X 



1-550 1-600 



X 

 X 

 X 

 X 



Copper sulphate 

 coefficient. 



300 400 



1 20 



=160 



Grasselli 

 . Chemical Co. 



L. .S. 

 (111. 1-40 



15 



30 

 45 



() 

 () 

 O 

 O 



o 

 o 

 o 







X 



o 

 o 

 o 



X 



o 

 o 

 o 



X 

 X 

 



o 



X 

 X 

 X 



o 



X 

 X 

 X 

 X 



350 550 

 1 20 



=183.5 



Copper Sulphate 

 Standard 



Copper Sulphate 

 20% solution 



Fungicide 



Ammoniacal 

 Copper Carbonate 

 lOOx standard 



5 

 15 

 30 

 45 



15 

 30 

 45 



1-1 





 O 

 O 

 O 



() 



o 

 o 

 o 



1-5 



X 







o 

 o 



X 

 X 



o 







1-10 



X 

 X 



o 

 o 



X 

 X 

 X 



o 



1-15 1-20 1-25 



X 

 X 







o 



1-10 1-20 1-30 1-40 



X 

 X 

 X 

 X 



X 

 X 

 X 



o 



1-50 



X 

 X 

 X 

 X 



X 

 X 

 X 

 X 



1-30 



X 

 X 

 X 

 X 



10 



+ 



30 



20 



= 1.75 



1-1 



1-5 



1-10 1-15 



1-20 



+ 



10 



25 



= .30 



