262 Early Studies in Bacterial Plant Diseases 



Of Smith's work on fungous diseases of plants caused by para- 

 sitic Fusaria, H. W. WoUenweber has said: ^* 



The opening up of the Verticillium problem we owe to Reinke and 

 Berthold (1879), that of the whole Fusarium problem to Erwin F. Smith 

 (1899). The latter investigator obtained the first conclusive results in the 

 etiology of the watermelon wilt by securing 500 successful infections by 

 simply inoculating the soil with pure cultures of the vascular parasite. 

 He considered the organism a variety of the same species as causes cotton 

 and cowpea wilt. The parasite of watermelon wilt was not infectious to 

 cototn or cowpea, nor to tomato or potato, through soil inoculation. 



Dr. Smith also discovered a very peculiar fact. A perithecial stage 

 (Neocosmospora) was frequently associated with the parasite on cowpea, 

 especially on parts already killed. In pure cultures derived from a single 

 ascospore, all stages (mycelium, conidia, ascospores) of Neocosmospora 

 redeveloped the ascus stage, and the conidia in subcultures of the fungus 

 were similar to the small conidia of the parasite. Cowpea inoculations with 

 the fungus derived from ascospores of Neocosmospora failed, however. 

 Since this failure might be due to the fact that the natural method of 

 infection had not been discovered, the author did not feel justified in 

 regarding it as proof of saprophytism. Therefore, he chose the hypothesis 

 that the vascular parasite and the ascomycete Neocosmospora were 

 identical. 



Not until 1899 did Smith propose his new genus Neocosmo- 

 spora, and then he was unsure whether it was " one fungus, or 

 three." ^^ Nevertheless, he had '" opened up a new field of plant 

 parasitism," had been, he believed, the first to publish on " soil 

 infections due to Fusariums, some of which are as destructive as 

 Peronosporas," *^° and through his work " special attention [had 

 been drawn] to the fact that this form-genus, hitherto generally 

 supposed to be saprophytic, contained a number of very destruc- 

 tive soil parasities." ^^ 



On March 26, 1892, Smith had read before the Botanical 

 Seminar of Washington a paper on " Relations of the Soil to Plant 

 Nutrition." That year Milton Whitney had outlined an elaborate 

 plan of soils investigation in the belief that some clue would be 

 found which might help to solve the problem of peach yellows. 

 Whitney was in charge of a division of soils investigation at the 

 Maryland Agricultural Experiment Station and later became chief 



^* Studies on the fusarium problem, Phytopath. 3(1): 24-50, Feb. 1913, at 36. 

 " Bull. 17, U. S. Dep't Agric, Div. Veg. Phys. and Path., 39, A6, 1899- 

 *" Synopsis of researches, op. cit., 22. 

 *^ Fifty years of pathology, op. cit., 22. 



