32 THE SCOLYTID BEETLES. 



operations can be directed and concentrated upon the principal 

 areas so that a large percentage of the timber can be cut, barked, 

 or otherwise treated before the broods begin to emerge, the desired 

 control may be effected with little additional expense, or even at a 

 profit. If tins method can not be adopted, the force should be 

 directed to removing as large a percentage as possible of the infested 

 bark from the standing infested trees or from those felled for that 

 purpose. The first work should be done in the principal areas and 

 larger patches. The work should be planned and executed with 

 the object of destroying the greatest possible number of broods for 

 the time and labor involved ; that is, if there are more infested trees 

 than can be barked within the specified time, and five or six times 

 as many insects can be killed by removing half of the infested bark 

 from three or four trees as could be done in the same time by remov- 

 ing all of the infested bark from one tree, the former procedure is 

 far preferable. 



HOW TO CONTROL A LIMITED ATTACK. 



Whenever it is determined that one or more species is attacking 

 and killing small patches of timber in a given locality or forest of 

 greater or less extent and that the bark of the living and dying trees 

 contains living parent adults and developing broods, prompt and, if 

 necessary, radical action should be taken before the adults begin to 

 emerge and fly. 



HOW TO MAINTAIN CONTROL. 



IN STATE AND NATIONAL FORESTS. 



In State and National forests, and in all other forests in which there 

 is an organized force of rangers and fire wardens or patrols, each officer 

 should be furnished with the necessary instructions for the location 

 of beetle-infested trees and with equipment and directions for taking 

 the necessary action whenever the conditions demand it. It has been 

 demonstrated that any intelligent ranger or manager can become 

 proficient in locating and marking infested trees with comparatively 

 little instruction in addition to that already published or conveyed 

 in special recommendations. 



It is not necessary that every isolated infested tree should be 

 treated, but it is of especial importance that all groups of infested 

 trees should receive prompt attention. 



IN PRIVATE FORESTS. 



Private forests should receive the same attention as reserves, but 

 this is often far more difficult on account of intervening forests . where 

 the owners either can not or will not give the matter the required 



