94 SOME INSECTS INJURIOUS TO FORESTS. 



(1) By the adoption or adjustment of certain requisite details in 

 forest management, in lumbering and manufacturing operations, and 

 in storing, transporting, and utilizing the products which, at the least 

 expense, will bring about the necessary reduction of the injurious 

 insect and unfavorable conditions for their future multiplication or 

 destructive work. 



(2) By the adoption of policies of control, based upon expert tech- 

 nical knowledge or advice relating to the species, habits, life history, 

 and natural enemies of the insects involved, and methods for their 

 control, supplemented by expert knowledge or advice on the prin- 

 ciples of technical and applied forestry in the proper management, 

 care, and utilization of the forest and its resources and still further 

 supplemented by practical knowledge and experience relating to 

 local conditions and facilities favorable and unfavorable for suc- 

 cessful application according to a given method or policy of control. 



(3) By reliance on technical advice furnished by recognized ex- 

 perts in forest entomology and forestry as a basis for success in prac- 

 tical application by the owner or forester. 



(4) By utilization of so-called matured timber, and especially 

 dense or pure stands of such timber, thus removing one of the favor- 

 able conditions for rapid deterioration through attacks b}^ wood- 

 boring insects or death through the attack of destructive bark-boring 

 or defoliating insects. 



(5) By the utilization of a knowledge of the principles of natural 

 control as a means of contributing to the efficiency of artificial control. 



(6) By prompt recognition of the first evidences of the work or 

 destructive outbreaks of the principal insect depredators, by authentic 

 identification of the species involved, and by prompt action in adopt- 

 ing the proj)er method or methods of control for the prevention of 

 losses. 



It should be remembered that as a rule it is useless to attempt the 

 extermination of an insect enemy of the forest or its products. It is 

 only necessary to reduce and w^eaken its forces at least 75 per cent, so 

 that it can not continue an aggressive invasion, but must occupy a 

 defensive position against its own enemies and become dependent 

 upon favorable conditions resulting from avoidable negligence and 

 mismanagement by the owners of the forests and the manufacturers 

 of forest products. 



While beneficial insects, beneficial birds, and beneficial diseases 

 exert a continuous and powerful influence toward the prevention of a 

 more extensive waste of forest resources, it has been repeatedly demon- 

 strated that they can not be depended upon always to prevent wide- 

 spread devastations or otherwine to work for the best interests of the 

 private or public owner by protecting the best trees and the best 

 tree species. 



