A CONTRIBUTION TO OUR KNOWLEDGE OF 



SILVER SCURF (SPONDYLOCLADIUM ATRO- 



VIRENS HARZ) OF THE WHITE POTATO 



J. J. Taubenhaus 



Texas Agricultural Experiment Station^ 

 (with plates 41-43) 



The white potato Is one of the staple foods in the United States. 

 With the increased cost of Hving, it is natural that more interest 

 should be directed to investigations of the diseases of that im- 

 portant crop. Silver scurf is a trouble which of late years has 

 attracted considerable attention from American plant patholo- 

 gists. Although much has been written, scientific data on the 

 nature of the disease as well as on the taxonomic relationship of the 

 causative organism are still wanting. The present paper Is the 

 result of two years' investigation carried on at the Laboratory of 

 Plant Pathology of the Delaware Agricultural Experiment Station. 



Historical. — Harz (2), in 1871, was the first to describe the 

 fungus Spondylocladium atrovirens, without, however, suspecting 

 it to be the cause of silver scurf. In 1897, Frank (5) described a 

 spot disease of the white potato, which he attributed to a new 

 fungus, Phellomyces sclerotiophorits Frank. The same disease, 

 which was fully described a year later (6), is now known to Ameri- 

 can pathologists as silver scurf. In 1903, Johnson (9) called 

 attention to Frank's Phellomyces disease as being serious In Ireland, 

 and causing there a scab and dry rot of the tubers. That Johnson 

 was dealing with what we now know as silver scurf is certain. 

 However, it is difiicult to account for his naming the disease a 

 "scab," unless the material with which he dealt was scabby. 



From 1897 to 1904, nothing new was added to our knowledge 

 of silver scurf. However in 1905-1907, Appel and Laubert (10) 

 and (11), in their work on silver scurf claimed that the sclerotia 

 of the fungus Phellomyces sclerotiophorits are merely the stromata of 



1 Of the staff of the Delaware Agricultural Experiment Station at the time of the 

 presentation of this paper. 



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