ea 4= 
of the National Park Service indicated that many new adults. of the 
mountain pine beetle will soon be ready to emerge fron infested sugar 
pines in that area. Broods of the western pine beetle are estimated 
to be from 2 to 3 weeks farther advanced than at the same date last 
year. Snowfall hus also been extremely light, with the result that 
it has been possible to keep control work going practically through- 
out the winter. Two projects in northern California, one on the 
Modoc and another on the Lassen National Forest, were started early 
in December and completed about March 1. Two large projects in 
central California, imgolving treatuent of areas in the Yosemite 
National Park and in Stanislaus Nationel Forest, were closed down 
late in December in anticipation of heavy snowfall which is usual in 
this pert of the Sierras. a very light grecipitation occurred, how- 
ever, and control work was resumed soon after February 1. These 
projects are now well along toward completion. It is considered 
desirable to complete all control work in the State by april 5, as 
it-is expected that emergence of the beetles may be under way by . 
that time. 
Mountain pine beetie sroduces two or more seasonal generations 
in sugar vping.--s report has recently been completed by G. R. Struble, 
-of the Berkeley, Calif., fieid laboratory, summarizing the seasonal 
end life-history studies of the mountain pine beetle in sugar ine, 
which have been carried on during the past 2 years. In the central 
Sierra region of California it has been found that this insect pro- 
duces two complete seasonal generations and a partial third. In the 
wiite pine region of northern Idaho the same species p»roduces but 
one complete seasonal veneration. In its California habitat this in- 
sect differs in other respects from the northern form. One important 
difference which was determined recently at the Berkeley laboratory is 
that of cold resistance of the larval form. Overwintering larvae col- 
lected from sugar vine in central California were killed by cold at 
temperatures from 12% to 7° above zero F.; those collected from white 
pine in northern. Idaho were not killed until subzero temperatures 
were reached, complete mortality occurring between -2.5° and -17.5° F. 
of bark-penetrating 
TOxLCHC vils dependent u:on temperature.-- 

Field experiments carried on during the seasons of 1932 and 1933 at the 
Berkeley, Calif., field laboratory with light minerel cils of kerosene 
‘base as a means of killing western pine beetle broods in the bark of 
ponderosa pine resulted in wide variation in the vercentage of kill. 
The best results were obtained during .ecricds of warm weather, indi- 
cating that toxicity of the oils had some reiation to temperature. 
uae 
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