344 



FORESTS 



FORESTS 



burning. [For further information, see Yearbook, 

 United States Department of Agriculture, 1908, 

 pp. 314-317.] 



The locust borer {Cyllene rdbinim, Fig. 489) is 

 a whitish, elongated, round-headed grub, which 

 hatches from an egg deposited by a black-and 

 yellow-striped long-horned beetle, found on, the 

 trees and on the flowers of goldenrod from August 

 to October. The eggs are deposited in August and 

 September in the outer bark on the trunks and 

 branches, and the young larvse pass the winter in 

 minute hibernating cells between the outer corky 

 bark and the living bark. In the spring they bore 

 through the inner bark and enter the wood. Their 

 presence is indicated in May, June and July by the 

 boring dust lodged in the bark and around the 

 base of the infested trees. 



The young hibernating borers may be killed from 

 November 1 to April 1 by spraying the infested 

 trunks and branches with kerosene emulsion, one 

 gallon to two gallons of water. The older borers, 

 after they have entered the wood, may be destroyed 

 in May to July by cutting out the worst infested 

 trees and burning them or immersing them in 

 streams or ponds. The cutting of locust for any 

 other purpose, however, should be done between 

 November 1 and April 1, so that the removal of 

 the bark from the utilized part of the trunk and 

 the burning of the tops will kill the young borers 

 before they enter the wood. New plantations 

 should be made where the locust is naturally free 

 from general injury, and seed for the purpose 

 should be from trees which show the least dam- 

 age. [For additional 

 information, see Bul- 

 letin No. 58, Parts I 

 and III, and Circular 

 No. 83 of the Bureau 

 of Entomr)logy, 

 United States Depart- 

 ment of Agriculture.] 

 The oak timber 

 worm (Eupsalis mi- 

 nuta) is a slender, 

 whitish, cylindrical 

 grub or worm, less 

 than an inch in 

 length, with the seg- 

 m e n t s toward the 

 head much enlarged, 

 and the last abdomi- 

 nal segment smooth 

 and rounded. These 

 worms hatch from 

 eggs deposited in 

 wounds in the bark 

 and wood of living 

 trees, and at first 

 bore almost invisible holes directly into the wood. 

 The burrows are enlarged and extended in all 

 directions through the heart-wood until the larvae 

 have attained their full growth. (Fig. 490.) They 

 then transform to adults within their burrows 

 and emerge the next spring or summer to repeat 

 the cycle in the same wounds or in the wood of 



dead trees, stumps and logs, either standing or 

 felled. An axe wound in a large healthy tree 

 may result in attack by this insect, and later 

 the entire heart-wood become perforated with so- 

 called pinhole defects. Wounds made by lightning 



Fig. 490. pinholes in oak, the 

 work of the oak timber worm. 



Fig. 491. 



Pinholes in chestnut, the work of the 

 chestnut timber worm. 



or other cause may result in the wood of the 

 entire trunk being thus rendered worthless for 

 stave timber, clapboards or first-class lumber. 

 This insect breeds in great numbers in the stumps 

 of dead trees and in the stumps and logs of 

 felled trees, and is ever ready to attack living 

 trees wherever a slight wound in the bark offers 

 an opportunity. To avoid the attack of this in- 

 sect on living trees, all injured or dead hard- 

 wood trees, as well as the logs of felled ones, 

 should be promptly utilized or burned, and newly 

 felled trees should be cut very close to the ground 

 and the brush tops burned over the stumps. Indeed, 

 the disposal of all places for the breeding of this 

 insect will always be an important feature in the 

 management of American hard-wood forests and 

 farmers' woodlots. [For additional information, 

 see Yearbook, Department of Agriculture, 1903, 

 pp. 328, 324 and Bulletin No. 35, "West Virginia 

 Agricultural Experiment Station, p. 294.] 



The chestnut timber worm (Lymexylon sericeum) 

 is somewhat similar in general form to the pre- 

 ceding, but is at once distinguished by the dark 

 brown, horny plate with toothed edges on the last 

 segment of the body. It hatches from an egg 

 deposited by an elongated, brownish beetle clothed 

 with fine silky hairs. The habit of this borer is 

 practically the same as the oak timber worm, 

 except that it is found principally in chestnut, 

 though it sometimes infests red oak and white oak. 

 It is exceedingly destructive to the heart-wood of 

 old chestnut trees (Pig. 491), and never fails to 

 enter the slightest wound in the bark on the trunks 

 and around the bases of the dead branches of liv- 

 ing trees. It also breeds in dead or felled trees, 



