202 MONTANA EXPERIMENT STATION. 



perience of other localities has distinctly shown that its injuries will 

 be more severe some years than others. For the present, at least, 

 Montana fruitgrowers should look upon it as a pest of first-class 

 importance. They should inform themselves concerning the 

 habits and appearance of the insect in all its stages and should 

 be on the lookout for it in the orchard. 



Spraying does not appear to be effective in killing the larvae 

 Should the moth be admitted to the nurseries of the state it would 

 be very unfortunate not only for the nursery men but also for the 

 persons who purchase trees from them. 



NATURAL HISTORY AND HABITS. 



The larva or so-called worm spends the winter in a temporary 

 cocoon or hibernaculum on the trees. These hibernacula are re- 

 markable objects in that they so closely resemble the bark and the 

 felty surface of the young twigs as to be very difficult of detection 

 even by a trained eye. They are closely secreted in crevices around 

 the buds or in the depressed scars that mark the spots where leaves 

 were attached. They are about one-sixteenth of an inch across and 

 though made principally of the silken secretion that is produced from 

 the silk organs of the mouth of the caterpillar, they contain enough 

 of the surface parts of the surrounding bark to make them very in- 

 conspicuous. 



Besides occurring on the twigs as has been described by various 

 authors, the writer has found them also under the scales of bark in 

 association with the hibernating larvae of the codling moth. 



In the spring of the year at about the time the buds are swelling, 

 the larvae, which are dark brown with black heads, emerge from 

 their winter quarters and crawl to the buds. Observation is lacking 

 in Montana as to the precise time, compared to the opening of the 

 buds, that they arrive. It is probable, however, that in this respect the 

 habits would not vary much between here and other climates, for 

 Ihe same conditions of weather revive both insect and plant 

 life. Without much doubt, while a few larvae arrive early enough 

 to make it necessary for them to bore into unexpanded buds in order 

 to get food, the majority of them reach the buds after they have 

 begun to open. In both cases, alike, the larvae, which at this time 



