PLANT DISEASES 381 
the Agricultural Experiment Station to tell him what he 
ought to know. 
Cabbage Yellows. — This disease is caused by a soil fungus, 
Fusarium conglutinans, which is not known outside of the 
United States. 
Effects. — The fungus attacks the roots of the plant either 
in the seed bed or soon after transplanting. It works 
greatest havoc during a hot, dry period, as warm soil favors 
its growth. The plants attacked soon become stunted 
and the foliage assumes a pale, lifeless, yellow color. The 
disease is often more severe on one side of the plant than the 
other, causing it to curve towards that side. The fungus 
enters through the roots and passes up to the stem and 
leaves through the vascular bundles which it soon clogs and 
destroys, as well as the tissue adjoining it. As the destruc¬ 
tion of the vascular bundles shuts off the plant’s supply of 
food-material and water, the lower leaves soon drop off 
through lack of sustenance, and the whole plant either 
becomes sickly and fails to head or dies outright, according 
to the severity of the attack. 
Destructiveness. — On fields moderately infected, from 50 
to 75 per cent of the crop is a loss, while in badly infected 
fields the crop is a total failure. 
How the Disease Is Spread. -— The fungus is carried from 
field to field in a variety of ways : for example, (1) by diseased 
plants from infected fields; (2) by water which drains from 
infected fields; (3) by wind blowing the dust from field 
to field ; (4) by vehicles, tools, and animals. 
Persistence. — Once introduced into the soil, it remains for 
long periods, experiments extending over fourteen years 
having shown it to be still present and active. Soil infested 
with this fungus is said to be “ cabbage sick,” but other crops 
grow well in it. 
Control Measures. —* Various measures have been tried 
as a means of eontrolling the disease: (a) Disinfection of 
