-6U3- 
WESTERN PIKE BEETLE 
Pol lowing three seasons of relatively light losses, an increase in activity 
of the western pine 'beetle ( Dondroctonus brevicomis Loci) developed during the 
1939 season in California. This increase is aggressive rad disturbing in several 
important areas, notably on the west side of the Sierra Nevada and Cascade 
Mountains in northern California. In contrast to 1937 • when but 350 million 
board feet were killed, it is tentatively estimated that the 1939 losses will 
amount to 550 million board feet. In ; the ponde.roeabpine stands, of southern Idaho, 
the western pine beetle is responsible for some loss, although for the most part 
the infestations of this beetle can be considered as normal# 
The western pine beetle was more active during 1939 than in the previous 
year in spite of better moisture conditions and a general improvement in tree 
health and vigor in Washington and Or gon, A check of 190 320-acre sample plots 
in eastern Oregon and Washington showed an increase of 6 percent in the number 
of ponderosa pines killed. The Deschutes subregion of central Oregon showed a 
5^-percent increase. Control operations were started on the Fremont, Deschutes, 
and Ochoco National Eorests and were continued on the Warm Springs Indian Resorva, 
tion, as " ? ell as on private lands in southern Oregon. 
TEE MOUNTAIN PINE BEETLE 
Epidemic infestations of mountain pine beetle ( Dendroc tonus monticolae Hopk, 
in sugar pine have been heavier than for any season during the last 10 years in 
California. These infestations are occurring in areas where recent lv there have 
been no similar, serious, extensive outbreaks# The mountain pine beetle con- 
tinued to show signs of aggressiveness in Mount Rainier National Parle, where in- 
festation increased slightly over that of 1938# A maintenance control program is 
in effect in the park and it is hoped that with intensified efforts the infesta- 
tion will bo reduced to an endemic status by 1940, During the last season there 
has been no material change in the status of the bark beetle infestations of the 
Northern Rocky Mountain region. The mountain pine beetle continues to take an 
annual toll from the "Elite pine forests of Idaho and Montana of at least 0#7 per- 
cent of the total volume. Although responsible for some losses of whitebark pine 
along the higher elevations of the Continental Divide, there are only light 
scattered infestations of the mountain pine beetle within the lodgepole pine 
areas. Infestations, of the mountain pine beetle in limber pine and lodgepole 
pine are still serious on the Washakie National Forest, over a million infested 
tre --s being reported, 
DOUGLAS EIR BEETLE 
The Douglas fir beetle (D, ps eudotsugae Hopk.) occurs in epidemic numbers 
in many Douglas fir stands, in the Northern Rocky Mountain region, where severe 
losses nave occurred and aro still occurring. The insect became epidemic in the 
Douglas fir stands along the central and southern coastal area of Oregon, where 
numerous groups of trees were killed on the Siskiyou National Forest and the 
surrounding area. This outbreak is considered as a typical local "flare-up," 
cnaracteris tic of this insect in the region west of the Cascade Range. Presumably 
the population built up in tre^s killed by fires that burned over this country 
for the last several years. No control program is considered feasible. The wide- 
spread outbreak of the Douglas fir beetle in western Wyoming is still maintaining 
itself, where it is estimated that there are 500,000 infested trees on the Wash- 
