BIRD ENEMIES OF THE CODLING MOTH. 



By W. L. McATEE, 

 Assistant Biologist, Bureau of Biological Survey. 



RELATION OF BIRDS AND INSECTS. 



Most birds are to some extent insectivorous, and many species live 

 almost exclusively upon insects. There is no doubt that their com- 

 bined attack has an important influence on the numbers of the 

 insect army. In spite of birds and other enemies, however, it not 

 rarely happens that certain insects suddenly increase in numbers 

 and threaten great damage locally to crops. Instances of the sup- 

 pression by birds of such strictly local outbreaks of insects are 

 numerous. Rarely, however, do they exercise a noticeable degree 

 of control over an insect so widely distributed and so important 

 economically as the codling moth. Nevertheless, since 1746 nearly 

 all entomologists who have published accounts of the codling moth 

 have paid high tribute to its avian enemies, and they are almost 

 unanimous in declaring birds to be the most efficient natural enemies 

 of the pest. 



LOSSES DUE TO THE CODLING MOTH. 



The experts of the Bureau of Entomology state that the codling 

 moth causes greater loss to apples and pears than all the other 

 insect enemies of these fruits combined. They estimate the damage 

 the insect does to the apple crop of the United States at approxi- 

 mately $12,000,000 annually. 1 If account be taken of expenses 

 incurred in attempts to control the insect, as for labor, arsenicals, 

 and spraying apparatus, an additional sum of probably not less 

 than $3,000,000 or $4,000,000, or a total of at least $15,000,000, must 

 be charged to the presence of this insect in the apple orchards of the 

 United States. 



LIFE HISTORY OF THE CODLING MOTH. 



The life history of so important a pest has, of course, been care- 

 fully studied. It has been found by entomologists that as a rule the 

 eggs are laid upon the leaves or the fruit. There are usually two 

 broods of the insects and consequently two periods of oviposition, 

 namely, in early spring and in midsummer. The eggs hatch in 



1 Yearbook, U. S. Dept Agric., p. 435, 1907. 



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