26 INSECT AND FUNGOUS ENEMIES OF THE APPLE. 
of solution should be added to control the codling moth, curculio, 
and other insects. 
Spray the trees (1) when the cluster buds open, just before bloom- 
ing; (2) as soon as the petals fall; and (3) two or three weeks 
later. Varieties only slightly affected by scab, especially in the 
South, do not require the first application of this series, the two 
sprayings after the petals fall being sufficient to prevent the disease. 
On the other hand, in New England an extra application about the 
middle of August may be required to prevent late scab infections 
on some very susceptible varieties. 
BITTER ROT. 
ECONOMIC IMPORTANCE. 
In sections where it is prevalent bitter rot is the most dreaded of 
all the common apple diseases. After the fruit has been safely nursed 
through the attacks 
of scab and the cod- 
ling moth and is 
about ready to be 
harvested an out- 
break of bitter rot 
may destroy the en- 
tire crop of some 
varieties without 
much warning. It 
is rather spasmodic 
in its appearance, 
depending largely 
on weather condi- 
tions. Hot weather 
with plenty of 
moisture is essen- 
tial to the rapid 
development of the 
disease, and it 
therefore does not occur to any serious extent in the more northern 
parts of the apple belt nor in the drier sections of the West. It is well 
distributed throughout the Southern States where apples are grown, 
extending into southern T]linois, and has in the past destroyed several 
million dollars worth of apples during a single season. However, in 
recent years, since its treatment has been better understood and more 
thoroughly put into practice, the annual losses have not been so great. 
Fie. 15. 
Apple affected with bitter rot. 
CHARACTER OF THE INJURY. 
The bitter-rot disease appears on the fruit as a circular brown spot 
with concentric rings of fruiting pustules. (See fig. 15.) The 
492 
