22G 



Gill (J. B.). Important Pecan Insects and their Control.— C/. S. Dt'pt. 

 Agric, Washington, D.C., Fsumers' BxiW. no. 843, September 1917, 

 48 pp., 54 figs. [Received 7th March 1918.] 



The pecan tree {Carya olivaeforniis) is subject to the attacks of 

 many insect pests, some of which injure the nuts, some the foliage 

 and shoots, and others the trunlc and branches. 



The most important insects injuring the nuts are : — Acrobasis 

 hebescella, Hulst. (pecan nut and case-bearer), which in its larval 

 stage attacks the immature nuts, one larva often destroying several 

 nuts before attaining its full groAvth. This moth, as well as an allied 

 species, A. car y Ivor eUa, Rag., has often been reported as destroying 

 one-third to three-fourths of the total wild pecan crop in Texas. It 

 has three generations during the year and hibernates in the larval 

 stage. Moths from these larvae emerg^e in May and oviposition 

 begins soon afterwards. The eggs are always laid on the calyx end 

 of the nut and hatch in from 5-7 days. The larvae immediately 

 bore into the young nuts and begin feeding, weaving a tube-like mass 

 of frass and silken threads. The larval period lasts from 22-29 days, 

 and the pupal period for 9-13 days. 



Moths of the second generation emerge from the middle of June 

 to the begimiing of July, the larvae of this brood being less destructive 

 than the earlier ones. The third generation appears during the first 

 three weeks in August and the larvae do little or no damage to the 

 nuts, which by this time are beginning to harden. 



The best method of control against this insect is spraying with 

 lead arsenate at the rate of 1 lb. powder, or 2 lb. paste, to 50 U.S. 

 gals, water, to which should be added the milk of lime from 3 lb. 

 slaked lime. Three applications are required, the first just after the 

 nuts have set, when they are about the size of garden peas, the next 

 a week or ten days later, and the last, four or five weeks after the 

 second application. 



Another pest damaging the nuts is Cydia {Laspeyresia) caryana, 

 Fitch (pecan shuckworm), the larva damaging the nut by boring in the 

 husk and preventing its natural separation from the nut shell and 

 the proper development of the kernel. They also lessen the market 

 value of the nuts by leaving a sooty trail on the shells. The earlier 

 generations attack the young green nuts, eating out the interior and 

 causing them to fall, this being especially the case with the various 

 species of hickory which are also attacked. This moth, of which 

 there are from 1 to 3 annual broods, oviposits on either the nuts or 

 the foliage, the eggs, which are laid singly, hatching in about 5 days. 

 The larval stage lasts for three or four weeks, pupation taking place 

 mthin the green nuts, or in the shucks of mature fruits and lasting 

 for from 9 to 45 days. The insect hibernates in the larval stage in 

 pecan and hickory shucks either on the ground or on trees, the maxi- 

 mum emergence occurring during the last two weeks of March. 



The only practicable control measures are the gathering and burning 

 of all shucks immediately after the harvesting of the nut crop, and 

 the cutting down of hickory trees in the immediate vicinity of the 

 orchards. 



The nuts are also destroyed by Balaninus caryae, Horn (pecan 

 weevil), an insect very widely distributed throughout the country and 



