ADDITIONAL DATA ON THK LOCITST BORER. 39 



natural pri-o^ th. It will Ix' found, however, that no area of consid- 

 erable extent, even in such localities, is entirely free from this and 

 other destructive insect enemies, and that certain precautions and 

 well-planned methods of manat^ement with reference to the control of 

 the latter will l)c necessary. 



MANA(JEMENT OF i'LANTATlONS TO PRKVEXT INJURY. 



In the first |)lace it is necessary, in order to provide against future 

 losses from the l)orer. that a thorough survey he made in May and 

 June, not only of the area to be utilized but of the entire neighbor- 

 hood for a radius of a mile or more from its borders, for the purpose 

 of locating and destroying scattering trees and groNcs which are more 

 or less seriously infested or dan)aged by the borer. It would seetn 

 that the control of such large areas, by purchase or under a plan of 

 cooperation between the owners of the land or trees, is one of the 

 most important re((uisites for success in preventing future losses from 

 the ravages of this and other insects in small as well as large planta- 

 tions. In fact, it is the Avriter\s opinion that, with this precaution 

 properly and continuously carried out, locust may be successfully 

 protected from the l)orer in any locality. 



In the subsequent management of plantations and of natural forest 

 and sprout growth it is important each 3'ear to locate and destro}' the 

 worst infested trees for the purpose of killing the borers in the wood, 

 and to conduct the thinning and commercial cutting operations during 

 the period between October of one year and April of the next, in 

 order to destroy the young borers before they enter the wood. 



Worthless, scrubby, borer- infested trees should l)e killed outright by 

 stripping the bark from 4 or 5 feet of the lower stem during August to 

 prevent sprouts and seed production from them, and at the same time 

 to destroy the eggs and young borers. Trees deadened in this manner 

 will usually be so completely killed that not a single root sprout will 

 appear. Therefore this method is of special value in preventing 

 sprout reproduction from inferior individual trees. 



SELKCTINi; AND BREEDINC HOHER-RESISTANT TREES. 



The fact that some trees ai*c moi'c or h'ss resistant to attack or injury 

 by the l)or(>r. while adjacent ones in the same grove are attacked year 

 after year and seiiously damaged, suggests bre«Hling races and varie- 

 ties of the s})ecies which would be pernianeiitly resistant. 



Breeding experiments have been b(>gun in cooperation wiih th(^ 

 Bureau of Plant Industiy and the Forest Service^, but it will retjuire 

 several years to get detinite results. In the meantime, however, it is 

 imi)ortant that seed and cuttings for conunercial planting should be 

 selected, as far as possible, from trees w hich show l(>ast damage from 



