28 
Colorado Experiment Station 
Powdery Miijdew. —A common disease attacking all parts of 
the cucumber. This trouble has the general characteristics of all 
pov/dery mildews. At first the diseased stems are covered with 
whitish, powdery, circular spots. Later, these spots spread and may 
cover the entire leaf, which becomes distorted and retarded in its 
growth. Infection is found mostly on the upper surfaces, and on 
older leaves. Stems are similarlv attacked. Blossoms attacked fail 
to set their fruit. Diseased fruits develop the same symptoms as 
leaves. Such fruits become distorted and bitter. 
Control .— (i) x\pply flowers of sulfur with a good dust spray¬ 
er. The sulfur must be distributed to every part of the plant. Vines 
should be sulfured i to 7 times. 
(a) First application, when the shoots are a foot long. 
(b) Second application, at the first sign of the mildew. 
(c) Later applications, as need indicates and according to 
the weather. Less sulfuring is necessary during hot, 
dry weather. 
CURRANT. 
Canker oe Canes. —This disease has become prevalent in 
certain sections of the state. Apparently healthy canes may bear 
the fungus, which causes the trouble, for several years. The first 
indication of the disease is ^^ellowing of the leaves and early color¬ 
ing of the fruit. . Positive evidence of the presence of the canker 
in a patch of currants is the appearance of pinkish, cushion-like 
masses on dead canes (Plate VII). 
Plate VII. Canker of currant canes. The cushion-like bodies seen scattered over the 
canes are pinkish in color. 
