530 Journal of Agricultural Research voi. xii. No. 9 



by Stevens and Wilson (25), with an additional statement of the disease 

 by Wilson (29). They attributed this disease to Fusarium vasinfectum. 



No inoculations of okra plants with F. vasinfectum are recorded by 

 Atkinson, Clinton, Smith, or Stevens and Wilson. A species of Fusarium 

 was found constantly associated with the wilt of okra, and the disease 

 was regarded as the same as the cotton-wilt. Orton {16) states that in 

 his experience okra has contracted the disease when planted in fields 

 affected with cotton-wilt. 



Wollenweber (jj, 32) reports a \vilt disease of okra similar to that 

 previously attributed to Fusaritim vasinfectum; but Verticillium albo- 

 atrum Reinke and Berthold, instead of the Fusariumu fungus, was con- 

 stantly present in the vascular ducts. Successful inoculations were secured 

 with V. albo-atrum, and the fungus was recovered from the wilting plants. 



It would appear that there are two similar wilt diseases of this crop 

 induced by two quite different vascular parasites. It was for the purpose 

 of testing this latter hypothesis that the investigation herein recorded 

 was undertaken. While okra as a crop is restricted in general to the 

 home garden and is relatively of little importance, a study of the wilt 

 diseases of this plant is of general significance to the whole problem of wilt 

 disease. 



THE GENERA VERTICILLIUM AND ACROSTALAGMUS IN RELATION TO 



WILT DISEASES 



Verticillium albo-atrum was first described by Reinke and Berthold (22) 

 in 1879 as the cause of a wilt disease of potato {Solanum tuberosum) in 

 Germany. This appears to be the earliest record of species of Verticillium 

 associated with wilt disease. The work of Reinke and Berthold was 

 generally overlooked until the investigation of the leafroll (Blattroll- 

 krankheit) and similar diseases of 5. tuberosum brought it again to the 

 attention of pathologists. Recently the presence of V. albo-atrum in 

 wilting potato plants has been noted by several investigators : Appel (2) , 

 Spieckermann (24), Pethybridge (18), {19), Stormer (26), Wollenweber 

 and Schlumberger {34), Wollenweber (50, 31, 32), Orton {17). Wollen- 

 weber {31, 32) reports this organism as the cause of a wilt disease of a 

 S. tuberosum, S. melongena, and Abelmoschus (Hibiscus) esculentus. A 

 similar disease of snapdragon (Antirrhinum sp.) was described by 

 Brown (4) and the causal fungus determined by the present writer as 

 V. albo-atrum. V. dahliae, a species closely related to V. albo-atrum, is 

 described by Klebahn (14) as the cause of a wilting of dahlias. Aderhold 

 (i) also mentions a species of Verticillium in connection with thrombosis 

 of currants (Ribes spp. — "Johannisbeere") and gooseberry (Ribes spp. — 

 " Stachelbeere"). 



The causal organisms of a series of diseases of several host plants 

 variously described as wilt disease, thrombosis, bluestem, etc., have been 

 relegated by the respective authors to the genus Acrostalagmus. Owing 



