58 
Colorado Expeiu:ment Station 
Shot-Hole (Cylindrosporium padi) (59)— This leaf spot disease 
affects not only the leaves 
but also the fruit. On the 
leaves small brown spots 
are formed which often 
drop out giving rise to the 
characteristic ‘‘shot-hole’’ 
appearance. Badly af- 
fected leaves usually turn 
yellow and drop. On the 
fruit the disease causes 
small reddish-brown spots. 
The injury from these 
spots, however, is usually 
less than that resulting 
from loss of leaves. 
Spraying with Bor- 
deaux mixture (3-3-50) or 
lime sulfur (1-40) com- 
bined with clean cultiva- 
tion is said to be effective 
in controlling the shot-hole disease. The spray should be applied first 
when petals fall, followed by a later application in about two weeks. 
It is well to add about one pound of arsenate of lead powder to the 
spray to control chewing insects. This is also said to add to the 
effectiveness of the spray. 
Shot-hole disease of cherry and plum. 
Brown-Rot (Sclerotinia cinerea) (2‘2), (‘23) — This is not a com- 
mon disease in Colorado. It is the same as the brown rot of peach 
and other stone fruits. See Peach. 
CUCUMBER 
Bacterial Wilt (BaciTus tracheiphilus) — Bacterial wilt is common 
in Colorado on cucumber, cantaloupe, squash and other cucurbits. 
The disease is characterized by a wilting of the leaves and runners. 
There is no indication of decay or other injury to the roots or stems. 
The wilting is caused by liacteria which gain entrance into the ])lant 
by means of the bites of insects. The bacteria once in the stein 
multiply rapidly and plug the watei* tubes thus (‘aiising the plant to 
wilt. 
Since the disease is spread by biting insects the best way to 
control it is by spraying to control such common insects as the sfiuash 
bug and cucumber beetle. 
Tveniove and bui*n affected ))lants at oinn*. 
