28 SOMK INSECTS INJURIOUS TO FORESTS. 



past summer and tlu> local ion of t lie lar<2;i'r clumps and patches of infested trees within such 

 sections; then, if the locations of the infested areas and clumps are indicated on a map, it will 

 aid materially in plaiminfij efl'ectual opei'ations. If you could conduct j^our lof^ging opera- 

 tions in these sections and utilize the infested trees the desired results would be accomplished 

 without much expense. It is not necessary that all scattering infested trees should he felled 

 and barked, but it is of the greatest importance that all of the larger clumps and patches 

 within the worst infested areas should be thus treated within the period mentioned. If this 

 can not be done this year, the work of locating infested areas should be conducted next sum- 

 mer (190G), in order that the more important sections may receive attention next fall and 

 winter. 



We shall hold ouisclvcs in readiness to give you further information and suggestions on 

 subjects which ma}' not l)e clear to you, and whenever there is doubt al)ont the insect or its 

 work specimens should be sent to us for authent ic identification. 



In response to this letter, Mr. Hoover wrote: 



We are most gratified with the information given us ami feel that it will be of much value 

 to us in our woods operations. * * * 



The ferreting out of the insect pest and advising a way to combat it is a work of great value 

 1,0 the country and of especial interest to all persons interested in forests, and wc; wish to add 

 our word of appreciation of the service of your Bureau. 



Your letter is clear and explicit, and we will be glad to take advantage of your suggestions 

 in our logging operations and have conveyed the information to other lumber companies 

 operating in this vicinity. 



Doctor IT()j)kiiis has, since then, prepared the followino; additional 

 recommendations and summary: 



TRAP TREES. 



With our })resent knowledge of the life history of the western pine- 

 destroyer and its habits of attacking girdled and felled trees, it is evi- 

 dent that trap trees'* m<^y prove effective in keeping the insect under 

 control, especially in localities where only a few trees are being killed 

 each year or after a large number of the infested trees have been felled 

 and barked in a l)a(lly infested locality. 



The time to girdle and fell trees to catch the first generations would 

 be about the middle of June, the bark to ])e removed and burned in 

 about 20 to 25 days, or before the broods emerge. Girdled or dead- 

 ened trees are prepared by the "girdle to heartwood" method — that 

 is, cutting through the sapwood all around the trunk 3 or 4 feet above 

 the base or as high al)ove the l)ase as convenient to chop ; for this pur- 

 pose large, inferior trees should be selected. 



Felled trees should be lodged or allowed to fall on logs, rocks, etc., 

 so that the j^rostrate trunks will be as far as possible from the ground. 

 Trees pre])ared in this manner will usually be attacked by swarms of 

 the beetles, which will excavate galleries in the bark and deposit their 

 eggs. After the eggs have hatched and (he larva^ are about full grown, 

 the removal and burning of the bark will eirectually destroy the broods 

 and thus contribute greatl}" to reducing the numbers of the beetles — 



o Living trees girdled or felled at the proper time to attract the flying beetles to them and 

 away from healthy trees. 



