ET 
1916] 
GILMAN—CABBAGE YELLOWS 77 
tures within limits, eaused а more rapid fall of Ше leaves. 
These facts give a possible explanation of the results found 
with cabbage yellows. The hyphae of F. conglutinans in the 
fibro-vascular bundles cause a constant but slow drain on 
the water content of the plant, which causes the formation 
or the beginning, at least, of the formation, of the abscission 
layer. High temperatures, in addition to causing increased 
growth of the fungus, raise the transpiration and also stim- 
ulate leaf-fall; thus all the factors are cumulative in their 
effect. 
The reason that mechanical and chemical injuries to the 
stem did not cause similar symptoms may be explained by the 
fact that the plants wilted before sufficient time was given 
for the formation of the abscission layer and, therefore, the 
difference in symptoms. This theory also concurs with that of 
Humphrey in regard to the tomato blight, but a large amount 
of work is still necessary before it will be completely proven. 
SuMMARY 
Cabbage yellows is a wilt disease of cabbage caused by 
Fusarium conglutinans Wollenw. 
The fungus is a facultative parasite living in the soil, from 
which, under certain conditions, it becomes destructive to 
cabbage. 
The fungus has a high optimum temperature and is very 
resistant to drying—both in pure culture and in the soil. 
Inoculation experiments with Fusarium conglutinans in 
pure culture caused the disease in a large percentage of the 
trials. Control plants remained entirely free from the yellows. 
Fusarium conglutinans was recovered from inoculated dis- 
eased seedlings and again produced the disease upon inocula- 
tion. 
Variation in virulence of the cultures and in susceptibility 
of the host caused many artificial inoculations to be unsuc- 
cessful, resulting in less than 100 per cent infection. 
