BUREAU 01- ENTOMOLOGY AND PLANT QUARANTINE 
7 
localized areas where the insects appeared to be on the increase, and it 
is possible that the low point in the infestation cycle has been passed. 
Assistance was given Federal and private agencies in the control of 
the western pine beetle through application of sanitation-salvage log- 
ging, and a close check was maintained of results on earlier projects 
in California. Other agencies are adopting this method of logging in 
stands of ponderosa pine where the beetle hazard is hi<rh. Beetle- 
control logging projects have been begun on the Warm Springs Indian 
Reservation and the Fremont National Forest in Oregon, and on the 
Yakima Indian Reservation and Snoqualmie National Forest in 
Washington. Other areas will be included when the supply of equip- 
ment and manpower permits lighter cuts over larger areas. 
Two studies recently completed explain why certain trees and areas 
are more susceptible than others to pine beetle attack. One analysis 
demonstrates a relationship between ground cover and insect attack, 
and the other shows effects of root injury and soils on tree health. 
Both point to the importance of root development, soil, and competi- 
tion. Federal and private agencies interested in these studies have 
given valuable assistance and are already putting to use some of the 
results. 
SPRUCE BUDWORM OUTBREAKS CAUSE CONCERN 
An extensive outbreak of the spruce budworm in the central Rocky 
Mountain region has killed or weakened tremendous quantities of 
Douglas fir, alpine fir. white fir, blue spruce, Engelmann spruce, and 
ponderosa pine. Much of the timber in this area is of value for water- 
shed protection and recreational purposes. Previous attempts to con- 
trol this insect by spraying with lead arsenate around camp grounds 
and other special use areas have been only partially successful. A 
series of spraying experiments conducted in the spring of 1944 in 
cooperation with the National Park Service and the Forest Service 
indicate that control can be obtained by the application of DDT at 
the rate of 1 pound per 100 gallons of water. 
A widespread outbreak of the budworm has been in progress in 
parts of Ontario and Quebec for several years. The extreme destruc- 
tiveness of this outbreak, together with the present critical shortage of 
pulpwood. has caused timber owners in the New England and Great 
Lakes States to become very much concerned about the possibility of 
similar losses in the United States. Plans have been made for an 
intensive study giving special attention to development of forest- 
management practices that will reduce the likelihood of an outbreak 
or aid in the salvage of infested timber. 
IMPROVEMENTS IN AERIAL APPLICATION OF INSECTICIDES 
The most important development in work being conducted in coop- 
eration with the Division of Gypsy and Brown-Tail Moths Control 
has been the spectacular control of the gypsy moth obtained through 
the aerial application of DDT. A 20-acre tract of infested woodland 
located in Jefferson, Pa., was treated on May 3, 1914, with a concen- 
trated spray mixture at the rate of 5 pounds of DDT per acre. The 
spray, released through a specially constructed distributor, settled 
through the forest as a fine mist, which gave good coverage of exposed 
surfaces of trees, undergrowth, and the forest floor. Foliage was just 
