28 SOME INSECTS INJURIOUS TO FORESTS. 



past summer and the location of the larger 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 planning effectual operations. If you could conduct your logging 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 be 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 (1906), in order that the more important sections may receive attention next fall and 

 winter. 



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

 subjects which may not be clear to you, and whenever there is doubt about the insect or its 

 work specimens should be sent to us for authentic identification. 



In response to this letter, Mr. Hoover wrote: 



We are most gratified with the information given us and 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 

 to the country and of especial interest to all persons interested in forests, and we wish to add 

 our word of appreciation of thfe 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 Hopkins has, since then, prepared the following additional 

 recommendations and summary: 



TRAP TREES. 



With our present 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 " may 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 badly infested locality. 



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

 be about the middle of June, the bark to be 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 above the base 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 prostrate trunks will be as far as possible from the ground. 

 Trees prepared 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 the larvae are about full grown, 

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

 and thus contribute greatly to reducing the numbers of the beetles— 



a Living trees girdled or felled at the proper time to attract the flvini? beetles to them and 

 away from healthy trees. 



