JOIBAL (iFAGRICOLTURALffiSEMCH 



DEPARTMENT OF AGRICULTURE 



Vol. V Washington, D. C, November i, 1915 No. 5 



SOME POTATO TUBER-ROTS CAUSED BY SPECIES OF 

 FUSARIUM 



By C. W. Carpenter, ^ 



Scientific Assistant, Cotton and Truck Disease Investigations, 



Bureau of Plant Industry 



INTRODUCTION 



Deterioration of tubers of the Irish potato (Solanum tuberosum) is 

 induced by a variety of causes. Economically the most important of 

 these are the organisms Phytophihora infestans, Fusarium spp., bacteria, 

 and miscellaneous fungi, including Rhizopus nigricans. 



Phytophihora infestans, which is somewhat restricted to the northeast- 

 ern part of the country, does more or less damage each year, and occa- 

 sionally in epidemic form causes tremendous losses. Exclusive of P. 

 infestans, however, species of Fusarium are undoubtedly the most impor- 

 tant causes of tuber decay. Though never occurring in epidemic form 

 with losses comparable to those of late-blight, they are present wherever 

 potatoes are grown, taking their quota of the crop both in the field and 

 in storage. 



Several species of the genus Fusarium Link have been described as 

 causes of tuber- rots of Solanum tuberosum (Clinton, 3; Pizzigoni, 12; 

 Wehmer, 15; Smith and Swingle, 14; Pethy bridge and Bowers, 11; 

 Longman, 6; Manns, 7).^ In most cases prior to 191 2 F. solani (Mart.) 

 Sacc. or some species thought to be a synonym of it is given as the causal 

 organism. Until recently the chaotic condition of the genus Fusarium 

 has precluded careful work with clearly defined species. 



1 Having been associated with Dr. H. W. Wollenweber, of the Bureau of Plant Industrj-, during the 

 past two years, the writer has enjoyed the privilege of personal work with the species and strains cultivated 

 during this period in connection with his monographic study of the genus Fusarium. Any attempt to 

 work with the species of this form genus emphasizes the necessity of completing such studies. Owing to 

 Dr. WoUenweber's absence during the preparation and publication of this paper, he is not responsible 

 for the subject matter. It is regretted that his criticism of the results is lacking, particularly as the data 

 obtained force the author to conclusions which differ somewhat from Dr. WoUenweber's published opinions. 



- Reference is made by number to " Literature cited," pp. 208-209. 



For a list of the more important references to potato studies, see the following: Appel, Otto. Beitrage 

 zur Kenntnis der Kartoffelpflanze und ihre Krankheiten. I. In Arb. K. Biol. Anst. Land u. Forstw.. 

 Bd. s, Heft 7, p. 415-435. 1907. 



Journal of Agricultural Research, Vol. V, No. s 



Dept. of Agriculture, Washington, D. C. Nov. i', 1915 



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