would result from leaving them. That is, left by themselves 

 they do not constitute an important point of concentration; 

 and the insects from them and from other parts of the unit 

 would be apt to be attracted to other more important points 

 of concentration. In other words, the Bureau of Entomology 

 advocates spending the money on important centers of concen- 

 tration rather than for the removal of unimportant individ- 



trees which from their ver;- character will not breed 

 large quantities of insects. The effort to treat every in- 

 fested tree on the area laid out for a season's work means 

 the expenditure of a good deal of money on these less import- 

 ant trees, some of which may be near trees which must be cut 

 under any conditions and some of which may be located by 

 themselves on ridges difficult of access, where their treat- 

 ment would cost a great deal of money. 



To illustrate further, let it be supposed that the 

 money available does not permit covering an infestation unit 

 within one year, but that ''rhree years' operations will be . 

 necessary. Three yearly areas are, therefore, laid out to 

 be handled successively. During the first year all important 

 trees and groups of trees on the first area are treated. 

 Probably 10 or 15 per cent, of the trees actually infested 

 ./ill be overlooked, for one reason or another, and 10 or 15 

 per cent, more are of such a character as not to be worth 

 treating. In the second year there may be a greater or less 

 degree of infestation of the area first covered. Heretofore 

 the Service has attempted, in this case, to treat during the 

 second year every tree which has become infested on the area 

 covered during the first year, as well as to cut all of the 

 trees infested on the area laid out for the second year's 

 operations. In re-trerting the first area the Service has 

 thus aimed at the complete elimination cf all broods, on the 

 theory that this treasure is necessary and justified for the 

 protection of the Forest values which are threatened. The 

 Bureau of -Entomology, on the other hand, v/ould go over the 

 fi^st area during the second year and treat any Irr^e and 

 important trees or groups which were found to have been at- 

 tacked; but it would not undertake any complete clean-up. 

 In fact, it would cut just as few trees as possible, prefer- 

 ring to spend just as much of the funds available as it could 

 on "virgin infestation" on one of the areas not previously 

 touched. If the backbone of the infestation is not broken 

 at the end of the second year, the chief efforts thereafter 

 would be devoted to the third area, still working in virgin 

 soil rather than spending much on clean-up work where re in- 

 festations have occurred on the first and second yearly are": 



-3- 



