IMPORTANT PECAN INSECTS AND THEIR CONTROL. 



39 



September. The beetles deposit 

 their eggs in. cracks or under bark 

 scales upon the trunk or larger 

 limbs. The young larva upon 

 hatching gnaws through the bark 

 and begins to feed upon the sap- 

 wood immediately beneath, mak- 

 ing a more or less irregular gallery 

 packed with sawdust castings, the 

 gallery usually being evident 

 through the bark. Some galleries 

 have a very tortuous or spiral 

 course (fig. 47), and because of this 

 the affected trees are often girdled. 

 If the trees are able to maintain 

 considerable vitality in spite of the 

 attacks, the larva? do not enter the 

 sapwood to transform to pupse, as 

 they do in dead and dying trees, 

 but transformation to pupa takes 

 place immediately under the bark, 

 a slight excavation being made in 

 the sapwood. One year is re- 

 quired for the complete develop- 

 ment from egg to adult. Because 

 of the different sizes of larvae that 

 may be found in trees at almost 

 any season of the year, many grow- 

 ers believe that the insect has more 

 than one brood. This, however, 

 is to be explained by the great 

 variation in rate of growth of the 

 larvre and the consequent varia- 

 tion hi time of emergence of the 

 beetles, this emergence taking 

 place any time from March until 

 early autumn. 



FIG. 47. The flat-headed apple-tree borer: Lar- 

 val burrow in trunk of young pecan tree. 



CONTROL MEASTRES. 



After borers have gained entrance to the trees nothing better can 

 be done than to examine the trees carefully and remove the larvae with 

 a knife. The point of infestation on the trunk or limb usually can be 

 detected by the discoloration and depression of the bark, which some- 

 times cracks open. In badly infested orchards the trees should be ex- 

 amined at least twice a year, and perhaps a third time would be advan- 

 tageous. In cutting out ''worms" great care should be taken not to 



