Bui. 82, U. S. Dept. of Agriculture. 



PLATE II. 



Four Tubers (A, B, 0, and 1>) Infected with Spongospora Subterranea Col- 

 lected in New Brunswick, Dominion of Canada, on October 1, 1913. 



They represent the scabby stage of the disease. The sori niiiy be either isolated or grouped, 

 us shown in .1 and B. The variation in size and general appearance of the sori is 

 brought out in Cand I>. In the tuber marked 1) the sori are only about half as large 

 and more superficial than in C. Two tubers infected with Oospora scab are shown as 

 E and F. 



