12 FARMERS ' BULLETIN 843. 



geiice thus covering a period of more than two months. It has been 

 determined, however, that the maximum emergence of moths 

 occurs during the last two weeks of March. Extensive observations 

 have shown that the vast majority of moths come forth before the 

 appearance of the pecan foliage and nuts, and this apparently ac- 

 counts for the extremely small numbers of first-brood larvae that 

 attack the pecan trees. The development of the foliage and nuts of 

 the pignut * and white hickory 2 is much earlier in the spring than that 

 of the pecan, and it seems that the emergence of moths is timed for 

 these host plants. In this connection it is interesting to note that 

 considerable damage always is done to the very small hickory nuts by 

 the first brood of larvae, while the very small pecan nuts seem to 

 escape such injury. Some first-brood larvae will be found attacking 

 the tender shoots of pecan, but the apparent reason for the immunity 

 from attack of the recently set pecan nuts is the fact that the emer- 

 gence of moths does not coincide very well with the development 

 of the nut. Since the moths are capable of flying some distance, it is 

 likely that for the purpose of egg-laying some of those emerging from 

 pecan shucks during the spring succeed in reaching hickory trees 

 growing adjacent to pecan orchards. 



The moths deposit their eggs on the young nuts or foliage, and 

 during the summer months the period of incubation lasts about 5 

 days. Upon hatching the larvae gnaw their way into the nuts by 

 making a pinhole entrance, and proceed to mine the shucks in the 

 nearly matured fruit, but some larvae bore into the interior of the 

 green nuts and cause them to drop to the ground. 



During the spring and summer the larvae usually feed from 3 to 

 4 weeks, and transform to pupae within the green nuts or the shucks 

 of the matured fruits. The length of the pupa stage is found to 

 range from 9 to 45 days. During the summer months it lasts about 

 11 days, while most of the pupae from overwintering larvae trans- 

 form to moths in 18 days, although some few moths do not issue] 

 for a considerably longer period. The pupation of the overwintering 

 larvae occurs from about the first of February until the middle of April. 



As stated before, the larvae of the first brood feed for the most \ 

 part on the small hickory nuts, but during the last days of June 

 and through July and August, although continuing their depreda-j 

 tions on the hickories, the larvae will be found attacking the green 

 pecan nuts. The first and second broods of larvae destroy the 

 interior of the nuts and invariably cause them to drop. The last 

 brood of larvae, which attacks the nearly matured nuts with hard 

 shells (fig. 11), feeds only on the shucks, in which they mine and 

 attain full growth before the advent of cold weather. They pass 

 the winter as larvae in the shucks on the ground or in shucks that 

 remain on the trees. 



1 Hicoria qlabra Britt. 2 Ilicoria alba Britt. 



