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A Summary of the Insect Loss 
\ Conditions revealed by the 
California Insect Survey, 1917.* 





























AREA AND VOLUME INCLUDED IN SURVEY:- This survey included the pine belt on 
the western flank of the Sierra Nevada Mountains of California from the Rubicon 
River as far south as the South Fork of the Tule River. Therefore, practically 
all the private and government owned yellow pine, Jeffrey pine, and sugar pine 
within the Eldorado, Stanislaus, Sierra, and Sequcia National Forests, and the 
Yosemite and Sequoia National Parks was covered, This represented a stand of 
(23h billion feet, or 18 per cent of the private and government owned timber in 
California, 
4 COST OF 1917 SURVEY AND ESTIMATE OF GOST FOR COMPLETING THE STATE:- In- 
cluding both the field expenses and the salaries of all the men engaged on the 
‘survey, the 1917 survey cost was $3200. Using this figure as a basis, the re- 
mainder of the pine timber of the State can be similarly coverd at a cost of 
$13000, about $7000 of which consists of estimated field expenses. If only 
field expenses are to be paid by the cooperators, it will be necessary to secure 
about $3500 from private owners for the examination of their lands. 
AMOUNT AND DISTRIBUTION OF THE INSECT LOSS:- Over 19 billion feet of the 
pine timber of the survey area have been devided into 55 so-called control units 
which will be used in the formulation of an insect-control policy. About 40 per 
cent of this pine timber is suffering from epidemic infestation, four-fifths 
of this epidemic loss being in timber which is both commercial and accessible 
‘and confined to 26 control units with a total acreage of 349,000 acres. In 1917 
this epidemic loss averaged less than one-half of one per cent of the total 
Stand, although on certain areas it was as high as one per cent, These Losses 
were proportionately as great in the private timber as in the government hold- 
ings, About three-fourths of the total insect loss on the whole survey area is 
confined to the epidemic infestations which by area constitute less than one- 
third of the survey area. These epidemics are confined to the watersheds of the 
San Joaquin, Kings, Kaweah, Tule, and Kern Rivers. 
Approximately 60% of the pine timber within the control units contained 
Only epidemic or normal infestation, in which the 1917 loss was usually not 
more than one-tenth of one per cent of the total stand. 
In case of the epidemic units a sufficient percentage of the infestation 
is recommended destroyed to reduce the insects to & point where their depredat- 
ion will be kept at a minimum by the same natural agencies which at present con- 
trol them on the endemic areas. 
Special reports on their respective areas were sent to the National Park 
Service and the private owners. Full general reports were made out for the con- 
sideration of the Forest Service and this Bureau. 
STORED PRODUCT INSECT INVESTIGATIONS. 
E. A. Back, Entomologist in Charge. 
F. B. Milliken who has been stationed in Wichita, Kans., during the past 
several years, has been transferred to New Orleans, from which point as head- 
quarters, he will make a survey of mill and grain storage conditions in the 
‘Surrounding region. 
. FOOTNQTE The Bureau of Entomology has prepared a separate brief summary of 
the strictly entomological phases of the survey. 
