46 



SCIENTIFIC NAME. 



For the present, at least, this fungus may be designated as follows: 

 Neocosmospora vasinfecta (Atk.) 



Syn. Fusarium vasinfectum Atk. 



On cottou. Probably also on okra. Parasitism not proved. Genetic connection 

 of various spore forms not proved. Cblamydospores not observed. 



a. Var. tracheiphila. 



Syn. Nectriella traclielpMla, Erw. Sm. 



On cowpca. Parasitism not pioved. Genetic relationshiji of ascospores, macro- 

 conidia and microconidia established. Cblamydospores not observed. 



/?. Var. nivea. 



Syn. Fusarium niveuvi, Erw. Sm. 



On vratermelon. Not known to occur on other Cncurbitacetc' Parasitism fully 

 established. One of the most destructive soil parasites known. Genetic connec- 

 tion of conidial stages fully established. Peritlieeia identical with the preceding 

 have been found on stems killed by the internal fungus, but the genetic relation- 

 ship has not been proved by exact culture experiuients. 



By "not proved" the writer does not mean that he has himself any 

 doubt whatever as to the parasitic nature of the cotton or cowpea fun- 

 gus or as to the genetic relationship of tlie various spore forms on 

 cotton and of the perithecia to the conidial stages on the watermelon, 

 but that these points have not been definitely settled by satisfactory 

 infection experiments and by deriving one spore form from the other 

 in pure cultures. Without such experiments the proof remains incom- 

 plete. The field evidence, however, of the parasitic nature of the cot- 

 ton and cowpea fungus is of the most convincing sort, i. e., the fungus 

 is always present in the vessels of the diseased plants, nothing else is 

 always present, and the disease occurs year after year on the same 

 soils. This constant association of the fungus with the cotton and 

 cowpea disease makes it reasonably certain (in the light of what has 

 been accomplished with the watermelon fungus) that abundant infec- 

 tions will be secured at no very distant day. The failures thus far 

 have probably resulted from a greater resistance on the part of cotton 

 and cowpea, or from the fact that the natural method of infection has 

 not been discovered. Possibly the cotton and cowpea may be subject 

 to infection only during germination or early stages of growth, or only 



' A destructive disease of cucumbers and muskmelons associated with a Fusarium 

 in the stem bundles has been reported from Ohio by Prof. A. D. Selby. The occur- 

 rence of a similar disease in muskmelons has just been reported from Connecticut 

 by Prof. William C. Sturgis. A Fusarial disease of squashes is known to the writer. 

 Possibly these diseases are due to the watermelon fungus, but the writer has not 

 observed diseases of other Cucurbitaceous plants in regions subject to the water- 

 melon wilt, and until cross-inoculation experiments have shown their identity it is 

 proper to consider these diseases as distinct. 



