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2-12-32 



into a gaunt liarren waste. If not checked pronptly such an infestation nay- 

 get beyond control, just as a fire sonotincs gets out of control. 



About five yeeirs ago, there was an oufbt-eak of the spruce bud worm 

 near the eastern entrance of the Yellowstone National park. That outbreak 

 threatened to destroy all the fir around the camp sites, and canyons, and 

 dude ranches. Tiie famous scenery of that section v/as saved from its ap- 

 parent doom by prompt spraying with cheoicals to kill those insects. In 

 sone cases, however, the forest and park administrators have been forced 

 to resort to protection of a strip of timber along the road. You canH 

 take elaborate spraying equipment througli the thick of the forest, and 

 oven v/ere that possible the cost would be prohibitive. In one place, Dr. 

 Craighead mentioned, the tourist finds himself flanlced by an apparently 

 beautiful forest of unmeasured depth, but a thousand feet back tlirough 

 tiiis scenic screen stretch miles upon railes of skeletons of a forest com- 

 pletely destroyed by insects. 



The worst of tree-killing insects seem to be the various ld.nds of 

 bark beetles, which "burrow into the bark of the tree, ,-ijid kill the tree 

 in a single season. To stop the spread of sone kinds of bark beetles it 

 is necessary to fell the infested trees, strip off the bark and bum it. 

 In case of thdn-bark trees, the treatment is a little different. The work- 

 er equipped with a compressed— air sprayer sprays the tree with fuel oil; 

 then igaitcs it, and scorches the bark and Id. lis the beetles. In the case 

 of the lodgepole pine beetle in the Crater I'Tational Park the infested tree 

 is merely felled in a north and south direction. The heat of the sun kills 

 the beetles. After a time, the v/orkers return and turn over the log, given 

 the sun a chance to ld.ll off the beetles infesting the other side. 



And, by the way, that lodgepole pine beetle threatens soon to de- 

 stroy ell the lodgepole pine in wl'-ich the Yellowstone ITational Paj:k and 

 nearby forests are clothed. Tliat devastating infestation started in the 

 Bladcfeet ITational Forest near the Canadian border in 1909 and has swept 

 along since then taking all the mature lodgepole pine. It also attacks 

 yellow pine, and western white pine, but doesnH attack fir, or even any 

 young pines below 8 inches in diameter. In a stand of timber which is 

 fifty per cent fir and fifty per cent lodgepole pine, that beetle vdll de- 

 stroy the lodgepole pine and leave the fir. But then the Douglas fir 

 beetle may come along and take the fir. 



It is estimated that bark beetles in western states destroy six 

 billion feet of timber, some $20,000,000 for lumber alone each year. This 

 docs not take into consideration the scenic value of s'uch trees as lodge- 

 pole pine in national parks worth much more than tliat. 



I just mention that to call your attention to what it sometimes 

 means for an insect outbrealc to get out of control. In the vast stretches 

 of our national parks and national forests you can see at once, tr^t it 

 miglit be easy for insect outbreairs to gain considerable headway before being 

 detected. That is the reason for this insect outlook service I mentioned 

 awhile ago. 



In that service. Dr. Crsdghead tells me, that the Bureau of Entomol- 

 ogy cooperates with the United States Forest Service and the ITationoJ. 

 Park Service. The men who first actually spot and report insect outbreaks 



