20 



FARMERS BULLETIN 843. 





The eggs hatch from about the middle of May until the latter part 

 of July or the first few days in August, depending more or less upon 

 the weather conditions. When the young larvae gnaw their way out 

 of the eggshells they commence feeding upon the portion of the 



leaflets immediately adjacent to the 

 place where egg laying or oviposition 

 occurred. (Fig. 23.) 



Throughout the summer and dur- 

 ing the early fall the larvae feed very 

 sparingly upon the foliage, and as they 

 extend their feeding quarters they en- 

 large their lit tie winding cases (fig. 23) , 

 which afford very good protection for 

 them. Although they may feed for 

 nearly three months, or even longer 

 in some instances, they rarely attain 

 a length greater than six one-hun- 

 dredths of an inch in the fall. Dur- 

 ing the latter part of September they 

 begin to seek winter quarters around 

 the buds, and here they construct 

 small, compactly woven, oval cases 

 known as hibernacula (fig. 24), and 

 by the middle of October practi- 

 cally all larvae have left the foliage and are to be found snugly pro- 

 tected in these cases. Shortly before the foliage begins to drop in the 

 autumn the little larvae abandon the leaves upon 

 which they have been feeding and attach their 

 winter cases securely to the buds and twigs. They 

 remain in hibernation until the latter part of March 

 or the first part of April, at which time the buds on 

 pecan trees usually begin to open. 



Just as the buds are opening, the larvae emerge 

 from their winter cases and attack the unfolding 

 leaves. Their pernicious feeding habits at this time 

 result in serious injury to the foliage and in reducing 

 greatly the yield of nuts. The larvae feed very vora- 

 ciously during the spring and some of them reach full 

 growth as early as the last days in April, but the ma- 

 jority do not attain full growth until Mayor early in 

 June. The larvae always transform to pupae within 

 their cases (fig. 25), and just before pupation takes place they spin a 

 flimsy layer of silk over the free end of their cases. The pupa 

 period has been found to cover from 16 to 23 days, the average being 

 a trifle over 17 days. The first adults make their appearance about 



FIG. 20. The pecan leaf case-bearer: Larva 

 and case. Enlarged. 



FIG. 21. The pecan 

 leaf case -bearer: 

 Pupa. Enlarged. 



