THE CODLING MOTH IN MASSACHUSETTS 



By A. I. Bourne and W. D. Whitcomb 



Importance as a Pest of Apples 



The codling moth (Carpocapsa pomonella L., Order — Lepidoptera; Family 

 — ^Eucosmidae) is a heritage of the modern fruit grower. Although a native 

 of southeastern Europe, this insect has now been established in this country 

 for nearly a century, and its increasing destructiveness has closely paralleled 

 the development of the commercial apple growing industry in the United 

 States. Estimates of the annual loss caused by the "apple worm" in this 

 country approach twenty million dollars and Massachusetts fruit growers pay 

 a proportionate share. It is generally considered to be the most destructive 

 insect enemy of the apple in the world, and much of our present knowledge 

 of orchard spraying has resulted from eflForts to reduce the losses caused by 

 this pest. 



In Massachusetts and other Northern States, the codling moth is less abun- 

 dant than in warmer regions, but even here it frequently damages 5 to 15 per 

 cent of the apples in sprayed orchards and 40 per cent or more on neglected 

 trees. 



Food Plants 



The apple is the favorite food of the codling moth. All varieties are at- 

 tacked, but in this State a slight preference is shown for early maturing va- 

 rieties such as the Williams and Gravenstein. Sweet or mildly acid varieties 

 like the Delicious and Hubbardston appear to be favored. The Baldwin also 

 becomes badly infested. This insect also breeds readily in crab apples, wild 

 apples, and hawthorn fruits. Pears, especially the Bartlett, Clapp's Favorite, 

 and Seckel are usually so severely attacked as to warrant the use of control 

 measures. Feeding in peaches, plums, cherries, and quinces is common, par- 

 ticularly when they are grown adjacent to infested apples or pears. In Cali- 

 fornia, the codling moth is a serious pest of English walnuts. 



Nature of Injury 



The larva, or "apple worm" as it is often called, is the only injurious form 

 of the codling moth. It burrows through the fruit, causing it to ripen pre- 

 maturely, to decay rapidly, and to be unmarketable as fresh fruit. The 

 typical wormy apple resulting from the feeding of the codling moth larva in 

 the fruit needs no description. In Massachusetts, the majority of the first 

 worms to attack the fruit enter inconspicuously through the calyx cavity and 

 leave it through the side. The round exit hole is very noticeable. Other 

 worms, particularly late in the season, both enter and leave through the side, 

 inflicting promment damage. 



