Identifier: powderyscabspong82melh (find matches)
Title: Powdery scab (Spongospora subterranea) of potatoes
Year: 1914 (1910s)
Authors: Melhus, I. E. (Irving E.), 1880-
Subjects: Potatoes Diseases and pests Powdery scab
Publisher: Washington, D.C. : U.S. Dept. of Agriculture
Contributing Library: U.S. Department of Agriculture, National Agricultural Library
Digitizing Sponsor: U.S. Department of Agriculture, National Agricultural Library

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Four Tubers (A, B- C, and D) 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 may be either isolated or grouped,asshown in A and B. The variation in size and general appearance of the sori isbrought out in Cand D. In the tuber marked D the sori are only about half as largeand more superficial than in C. Two tubers infected with Oospora scab are showrn asE and F. Bui. 82, U. S. Dept of Agriculture. Plate III.
Text Appearing After Image:
The Cankerous Stage of Sponqospora. It is this stage that is most destructive to the potato tuber. The cavities and large pustulescombine to cause malformation of the tubers. In C is shown a section through a tuberbadly infected with Spongospora. (A, B, D, and E are after Home. C after Giissow.) POWDERY SCAB OF POTATOES. 5 GEOGRAPHICAL DISTRIBUTION OF POWDERY SCAB. Spongospora seems to be quite generally distributed in northernEurope. As early as 1841 it was recorded as existing in Germany,and that it had existed for some time before this is suggested by thefact that among farmers the disease had come to be known by a com-mon name (Kartoflelraude). Frank more recently (1897) has men-tioned its existence in Germany, but he does not think it is generallydistributed. That it does exist to some extent, and possibly morethan Franks report indicates, is suggested by the following facts: In the spring of 1913 the Bureau of Plant Industry purchased 22different varieties of seed potatoes from

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