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FOREST ENTOMOLOGY 
A. D. Hopkins, Forest Entomologist. 





















Doctor Hopkins has completed his manuscript for a bulletin, entitled: 
"Ne latural Events and Laws as Guides to Research and Practice in Agriculture," 
Messrs. Edmonston and Hofer have been transferred from Colorado Springs, 
Colorado to a temporary field station at Tucson, Ariz., where they are engaged 
|@ study of the insects which are destructive to mosquito cordwood. 
Forest Insect Survey in California. 
The Assistant Forest Entomologist, J. M. Miller in charge of the forest 
sect field station at Ashland, Oregon, has submitted his report on the Forest 
Insect Survey of California so far covered, This survey was undertaken at the 
Solicitation of several private cwners in the region and was carried out under 
cooperative agreement between the Forest Service of this Department, the Nation- 
Park Service of te Interior Department and private owners, under the direct- 
don of this Bureau with Mr. Miller immediate charge and assisted by the field 
force attached to the Ashland, Station. The area, timber, costs and losses in- 
volved in this survey is thus summarized: 
j VALUE OF THE 1917 INSECT LOSS:- Assuming an average value of $2.25 per 
M for the sugar pine and yellow pine combined, the insect loss in the 1917 
epidemic in the commercial timber amounts to $23,000 on National Forest lands, 
and $15,000 in the private holdings, The 1917 epidemic loss in the Sequoia 
National Park approximates $4000, no epidemic losses now occuring on the Yosem- 
ite National Park. The 1917 loss on the survey area as a whole, including both 
epidemic and epidemic areas, private and Government lands, approximate $60,000. 
CONTROL MEASURES:- Control of the 1917 epidemic infestations in the 
commercial pine timber on the survey area, in accordance with the methods advo- 
cated by the Bureau of Entomology, will cost from $30,000 to $40,000 on the 
government holdings, and from $15,000 to $20,000 on the private lands. 
The complete working of all the survey area in a single year will yield 
by far the best control results, but such a procedure involves the difficulty 
of efficiently handling control work over such a large area with a limited 
number of men of requisite experience. 
LIMITATIONS ON THE DATA:- From year to year there is quite likely to be 
some fluctuation in the amount of the infestation on the 1917 survey area. As 
@ consequence, a change of insect conditions within the next few years and a delay 
in the inauguration of the recommended control work will necessitate correspond- 
ing changes in the estimated cost of control measures. 
The cost of control, even if it apparently balances the 1917 losses, will 
be more than balanced by its effectiveness for years to come. 
_ Three species of barkbeetles were found primarily responsible for the 
loss indicated: 
The western pine beetles (Dendroctonus brevicomis Lec. ) on yellow 
Z 
} The mountain pine beetle (Dendroctonus monticolae Hopk.) sugar pine 
and occasionally yellow pine. 
The Jeffrey pine beetle (Dendroctonus jeffreyi Hopk.) on Jeffrey pine. 

