THE DAVEY INSTITUTE OF TREE SURGERY 
scale, making vertical brood chambers, just under the bark, about 
one and one-half inches long and one-eighth inch in diameter. 
». In small pits on either side of this brood chamber, twenty to 
fty eggs are laid, which soon hatch into small legless grubs which 
begin burrowing through the cambium at right angles to the parent 
chamber. The end burrows gradually diverge from the others, 
spreading out fan-shaped, until the end ones finally run nearly 
parellel to the brood chambers. The grubs grow rapidly and con- 
tinue to extend their individual galleries until the latter are two 
to three inches long and the grubs are about one-quarter inch long. 
133. The winter is passed within the burrows as nearly full 
grown larve. In the spring the work is continued, and their 
growth completed the latter part of May, when the larve change to 
pupe. The adult beetles emerge about a month later through 
small round holes in the bark. Thus it will be seen that each 
colony will thoroughly undermine a portion of the bark from four 
to six inches square. 
134. The brood chambers are placed with such regularity 
over the trunk and larger limbs that it does not require a very 
large number of them to completely girdle a tree. In a section 
where serious damage is being done, several hundred of these colo- 
nies can be found in a single tree of moderate size. 
135. Control. From what has been said it is evident that this 
pest is a difficult one to control. In an outbreak covering a large 
area, or upon a large estate, the principal method of control con- 
sists in making a thorough inspection of the entire infested area 
in the early fall, and marking all badly infested trees and trees that 
have died since June of the current year. During the winter and 
spring all these trees are destroyed, or the bark removed and 
burned before May to kill the larve before they can emerge and 
spread to the healthy trees. If this is carefully done throughout 
the area, it will so reduce the number of borers that the natural 
means of control will prevent further serious injury. With small 
estates the greatest difficulty with this method is to secure the nec- 
essary cooperation among the different owners, so they will all 
carry out their part of the program. 
136. For small estates or valuable trees the following cam- 
paign is the one promising the best results: ; 
> 137. First—Remove and destroy all badly infested trees or 
parts of trees as before. 
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