Jan. 3,1921 Fusarium-Wilt of Tobacco 517 



comparison of these diseases. The Fusarium problem viewed as a whole 

 or even as that part which has to do with the nomenclature of the vascular 

 parasites, is recognized as being in a rather unsatisfactory state. Rather 

 uncertain precedent in naming forms, together with the plasticity in 

 physiology, and, one is tempted to say, in morphology of the forms 

 themselves, is the cause of the greatest difficulties encountered in this 

 problem. It is felt, therefore, that until a more detailed study of the 

 Fusaria causing wilt of tobacco and related plants can be made, it will 

 not be profitable to enter upon a review preliminary to discussion of this 

 subject. The review here presented, therefore, includes only the evi- 

 dence which we now have relating to Fusarium as a probable cause of 

 disease in the tobacco plant. 



McKenney (7) 1 in 1903 described a wilt disease of tobacco in North 

 Carolina as due to Fusarium. No proof of pathogenicity was obtained. 

 This disease was soon afterward studied by Stevens and Sackett (11) 

 and by Smith (10, p. 220-271) and was found to be a bacterial wilt 

 (Bacillus solanacearum), so that Fusarium could no longer be associated 

 with the disease. According to Smith no good evidence for a Fusarium- 

 wilt existed; but, reasoning from the universal distribution of Fusarium 

 and its occurrence as a vascular parasite in plants closely related to 

 tobacco, he predicted that a Fusarium-wilt of tobacco would be found. 

 Judging from the description of McKenney's disease and the virulence 

 attributed to it, the writer believes it could not have been Fusarium-wilt. 



Lounsbury (6) in 1906 reports a wilt disease of tobacco in the Kat 

 River Valley, Cape of Good Hope, which he states is, in his opinion, 

 not similar to the American (Granville) wilt. Bacteria, fungi, and 

 insects are all said to be concerned. Smith (10, p. 220-271) places it as a 

 doubtful bacterial wilt. To judge from the description, this may have 

 been a Fusarium-wilt disease, at least the South African disease should 

 again be checked up, if it still occurs. 



Petch (9) in 1907 reported a disease of tobacco in Dumbara, Ceylon, 

 which is said to be a "root-disease" causing "sudden and premature 

 ripening," killing out plants in patches. The stem is said to be dis- 

 colored at the base. A Fusarium was isolated from the roots. This 

 description may fit one or more diseases of tobacco. The isolation of a 

 Fusarium from the roots is, of course, of no significance. The "'sudden 

 and premature ripening in patches," however, suggests a wilt disease. 



Delacroix (2) in 1906 reported a disease of tobacco occurring around 

 Perigneux and Razoc, France, as due to a species of Fusarium which he 

 named Fusarium tabacivorum. The disease is said to resemble super- 

 ficially a bacterial cancer localized at the collar of the plant, and the 

 port of entry of the parasite is believed to be always an insect puncture. 

 The mycelium of the fungus was found to be present throughout the whole 



1 Reference is made by number (italic) to "Literature cited," p. 534-535. 



