14 BULLETIJM 571, U. S. DEPARTMENT OP AGRICULTURE. 



THE LARVA STAGE. 



During the season of 1913 eggs were found to hatch from about the 

 middle of May until the last days of July, and during the season of 

 1914 and 1915 from the latter part of May until the first few days 

 of August. The period over which the eggs are hatching depends, 

 of course, upon the time of emergence of moths, and it will be noted 

 in Tables I, II, and III that there was some variation in the issuance 

 dates of adults during 1913, 1914, and 1915. When the young larvae 

 gnaw their way out of the eggshells they commence feeding upon the 

 portion of leaflet immediately adjacent to the place where oviposition 

 occurred. Throughout the summer and during the early fall the 

 larvae feed very sparingly upon the foliage, and as they extend their 

 feeding quarters they enlarge the little winding or spiral cases which 

 afford them protection. Although the larvae may feed for nearly three 

 months or even longer in some instances, they hardly attain a length 

 greater than six one-hundredths of an inch. During the latter part 

 of September these larvae begin to seek hibernating quarters around 

 the buds, where they construct small, compactly woven, oval hiber- 

 nacula, and by the middle of October practically all larvae will have 

 left the foliage and may be found snugly protected in the hibernacula. 

 These little "worms" very wisely abandon the compound leaves upon 

 which they have been feeding, just a short time before the foliage 

 begins to drop in the autumn, in order to attach the winter cases 

 securely to the buds and twigs. 



The larvae remain in hibernation until the latter part of March 

 or the first days 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 hibernacula and attack the unfolding leaves. The perni- 

 cious feeding habits of the larvae at this time result in serious injury 

 to the foliage and in greatly reducing the yield of. nuts. During the 

 year 1913 the larvae reached full growth from about April 20 until the 

 latter part of June, but the majority pupated between May 10 and 

 June 10. During the seasons of 1914 and 1915 the majority of the 

 larvae were about a week to ten days later in reaching maturity. 



NATURAL ENEMIES. 



Three species of birds — the blue jay (Cyanocitta cristata), the mock- 

 ingbird (Mimus polyglottos) , and the orchard oriole (Icterus spurius) — 

 have been observed feeding upon the larvae of the pecan leaf case- 

 bearer. These birds, as well perhaps as those of other species, do 

 much to check the ravages of this pest, and their protection in the 

 pecan orchard should be encouraged. The blue jay very likely is 

 more beneficial than harmful to the pecan grower. In the writer's 

 opinion the good that this bird does in feeding upon injurious pecan 



