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. | MONTHLY LETTER OF THE BUREAU OF ENTOMOL 
> UNITED STATES DEPARTMENT OF AGRICULTURE 
eer = 
Number 77 ate ED rae en) a hee ee September, 1920, 
/ FOREST ENTOMOLOGY 
A. D. Hopkins, Forest Entomologist in Charge rieultm 
. { 
H. &. Burke of the Pacific Slope Laboratory at Los Gatos, Calif., spent 
; two days during the month at Santa Barbara, Calif., on the estate of the Hon. 
Julius Kahn, where there has been injury to the oak trees by the Pacific oak 
twig-girdler (Agrilus angelicus Horn), This borer kills the twigs by 
making a spiral mine under the bark and in the wood. Branches up to one 
inch in diameter are girdled and killed. A control project will be instituted. 
H. #. Burke and R. D. Hartman spent two days the first of the month with 
officials of the Pacific Telephone and Telegraph Co. at Watsonville, Salinas, 
Monterey, and Hollister, Calif., looking over the lead-shseathed acrial cables, 
where the suspension rings had been treated with soft tallow to prevent 
damage by the cable borer (Scobicia declivis Lec.). This method is apparently 
the only effective manner of preventing damage. Experiments with various 
lead alloys, chemical preventives, and different types of suspension rings, 
both at Los Gatos, Calif., and Falls church, Va., have all as yet proved 
ineffective, Some seasons the damage is quite serious, moisture penetrating 
through the holes made by the borer through the insulation and causing a 
short circuit at the time of the fall rains. 
J. H. Pollock of the Southern Rocky Mountain Pield Station at Colorado 
Springs, Colo., states that a great deal of damage is being done annually to 
young spruce trees in Colorado by a species of Pissodes, presumably P. . 
engelmenni Hopk., which kills the terminal shoot. On the eastern slope of 
the mountains, in the northern part of the State, almost one-half of these 
young conifers are being attacked -year after year by this insect. Also 
in the central part of the State extensive depredations are found. Here 
the damage is especially noticeable on the older trees located in the 
bottoms of canyons and swales where, because of an abundance of soil and 
moisture, the trees usually make the best growth. During recent years 
thousands of spruce seedlings have been transplanted in this State on 
areas where the forests have been destroyed by insects and fire, and in the 
near future these too will be exposed to the ravages of this insect unless 
controlled. 
During the month, at the request of the Small Arms Division of the 
‘Ordnance Department, U. S. A., a largs amount of black walnut and birch gun 
stock blanks and hand guards stored at New Cumberland, Pa., was inspected 
by Dr..T. BE. Snyder to determine the condition of the material with special 
reference +o preventing insect damage. Such damage can easily be avoided 
by the system of piling, classification into species, separation of sapwood 
from heartwood, and annual inspection, with particular stress upon the utili- 
zation of stock which has been seasoned the longest. 
At the Aircraft Storage Depot located at Middletown, Pa., where a 
larce amount of hardwood lumber is stored, there was found quite a little 
damage by Lyctus vowder-post beetles to the sapwood of black walnut. This 
