DYING HICKORY TREES.
Numerous magnificent hickories have been killed by the pernicious hickory bark borer in the vicinity of New York city. It has destroyed thousands of trees in the central part of the State, while recent investigations show that it is at work in the Hudson valley near Tivoli and probably is injurious in numerous other places. The severe droughts of the last two or three years have undoubtedly been favorable to the development of this pest, since the vitality of many trees has been lowered and they have thus been rendered more susceptible to attack by insect enemies.
The preliminary signs of injury, such as wilting leaves and dead twigs in mid-summer are exceedingly important because they indicate serious trouble before it has passed the remedial stage. Examination of injured trees at the present time may show particles of brown or white sawdust in the crevices of the bark, and in the case of some a few to many circular holes appearing as though they had been made by number 8 buckshot. This external evidence should be supplemented by cutting down to the sapwood. The exposure there of the longitudinal galleries 1 to 1½ inches long, about ⅛ of an inch in diameter and with numerous fine, transverse galleries arising therefrom and gradually spreading out somewhat fan-shaped, is conclusive evidence as to the identity of this pest. Only a little experience is necessary before one can recognize the work of this borer.
The insect passes the winter in oval cells as stout, whitish, brown-headed grubs about ¼ of an inch long, the beetles appearing from the last of June to the last of July. Badly injured trees are beyond hope and should be cut some time during the winter and the bark burned before the beetles can emerge; otherwise many will mature and attack other trees next spring. It is particularly important to locate the trees which have died wholly or in part the past summer, because they contain grubs likely to mature and then be the source of trouble another year. General cooperation in the cutting out of infested trees and burning of the bark as indicated above will do much to check this enemy of our hickories.
E. P. PELT.
State Entomologist.
The following "Press Notice" was issued by the U. S. Department of Agriculture under date of Nov. 15, 1911:—