PLATE io 
Injuries caused by Spongospora subterranea and other agencies: 
Fig. A.—Tuber showing the effect of flea-beetle injury. Note the similarity of this 
injury and the young sori of Spongospora subterranea. After being placed in storage 
a shrinkage occurs around the sori-like injuries similar to the desiccation injury around 
the sori of Spongospora subterranea. 
Fig. B.—Tuber showing a very early stage of infection by Spongospora subterranea. 
The points of infection show brown, fimbriate colonies. This condition is found in 
potatoes at time of harvesting. Spore balls are absent. 
Fig. C, D.—Tubers grown in infected soil in the greenhouse under exceptionally 
moist conditions and allowed a long growing season. These lesions resemble very 
materially the cankerous stage. 
Fig. E-—A potato from Ireland showing the cankerous stage. The powdery material 
is almost gone from the tuber, which appears to have been eaten by insects. 
Fig. F.—A tuber showing enlargement of the lenticels. This tuber was kept in a 
moist chamber for io days. Similar enlargements are often found in Florida-grown 
potatoes, and have also been seen in Delaware and New Jersey. Such conditions are 
often mistaken for the early stages of infection caused by Spongospora subterranea. 
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