18 
brood, the question of the control becomes easier for the Idaho fruit 
growers. 
OVERLAPPING OF GENERATIONS. 
The overlapping of the generations is one of the conditions which 
makes the control of the insect most difficult. In 1900, from July 7 
to about September 7, the writer could find all stages of the insect. 
In 1901 about the same conditions were noted. 
According to Mr. Hitt's experiments, the moths in the spring of 
1896 emerged during twenty-three days. 
The overlapping renders the spraying less effective than it would be 
if all the insects were in the same stage at the same time. 
This overlapping is accounted for by the fact that some of the 
insects, being in favorable situations, grow more rapidly, and others, 
in unfavorable places, lag behind. 
CAUSES AND CONDITIONS WHICH AFFECT THE NUMBERS OF 
THIS INSECT. 
There are many natural conditions which tend to decrease the num- 
bers of this insect in the Pacific northwest. Comparatively few of 
the eggs hatch. Infertility, excessive dryness, and the heat of the sun 
seem to be the causes of this. In 1901 thousands of the young larvae 
must have starved on account of not having apples to feed upon. 
No insect parasites were noted in 1901. A bird belonging to the 
creepers was noted at Payette. This bird was very active in hunting 
food on the apple trees, and without doubt destroyed many codling-moth 
larvae. Growers in this locality say that the bird is increasing in 
numbers. Many pupa? were found to be dried and shrunken, evidently 
killed by excessive dryness. In more humid sections bacterial and 
fungus diseases kill many. But if these unfavorable conditions and 
natural enemies alone are relied upon, almost every apple in an 
orchard in badly infested localities will be wormy. 
There are many reasons which may be assigned for the large num- 
ber and the great destructiveness of the codling moth in Idaho. The 
first and probably the most important fact in this connection is that 
the second generation is more numerous than the first, and does a 
larger part of the injury. This is doubtless due to the climate. It is 
also more difficult to combat this second generation with sprays than 
it is the first. The overlapping of the generation is another fact that 
makes the spraying more difficult. 
One reason for the great destructiveness of the codling moth in Idaho 
may be found in the life history of the insect. .V great many of the 
fruit growers have used remedies which are absurd. When the proper 
remedies were used they were not used in the proper manner, and 
hence failure resulted. 
