CODLING MOTH IN NORTHWESTERN PENNSYLVANIA. Ill 



maturity the larva seeks a hiding place beneath the rough bark of 

 the trunk of the tree and constructs a cocoon within which pupation 

 takes place about 1 week after the larva left the fruit. Some of the 

 larvse do not pupate at this time but winter, and the moths emerge 

 the following spring, together with moths from second-brood larvse. 

 The pupal stage — called the first-brood pupae, though the second set 

 of pupse of the season — lasts on an average 12 days. The emergence 

 period of this second set of moths, called first-brood moths, begins 

 in early August and lasts about 1 month. With the appearance of 

 new eggs, resulting from the first-brood moths, the life-cycle of the 

 first generation is completed, covering on an average 58 days. The 

 second-brood eggs hatch generally within 9 days and the resulting 

 larvse feed about 40 days, after which they enter hibernation, making 

 cocoons beneath the rough bark on the trunk of the trees. The life- 

 cycle of the second generation and part of the first generation is first 

 completed with the transformation of the insect the following spring. 

 The period covered by the different stages of the two broods for 1909, 

 as shown in figure 22, closely represents average conditions. 



The relative number of transforming larvse of the first brood is 

 variable under different seasonal conditions. 



The relative abundance of second-brood larvse depends more 

 upon seasonal conditions and food supply than upon the number of 

 transforming larvse of the first brood. 



Larvse of the second brood are always present in injurious numbers, 

 so that measures should be taken to combat the second as well as the 

 first brood. 



The time of the emergence of the spring brood of the moths is vari- 

 able under different seasonal conditions and depends largely upon 

 the relative lateness of the spring. 



The time of emergence of the summer brood or first brood of moths 

 is fairly constant and generally commences about the 1st of August. 



In the control of the codling moth with poison sprays three appli- 

 cations should be made in this section of the country. The first 

 application should be made after the blossom period just after the 

 petals drop, the second application from 3 to 4 weeks later, and the 

 third application from 9 to 10 weeks after the petals drop, or about 

 the 1st of August. 



