VI SOME INSECTS INJURIOUS TO FORESTS. 



The southern pine sawyer — Continued. Page. 



Injury to storm-felled timber by the southern pine sawyer 44 



Peciiniary loss 45 



Character of the insect 45 



Seasonal history 49 



Habits 51 



Natural enemies 53 



Remedies 54 



Bibliography 56 



Insect depredations in North American forests and practical methods of preven- 

 tion and control A. D. Hopkins. . 57 



Introduction 57 



Insect depredations in, North American forests 57 



Character and extent of depredations 57 



Insects cause the death of trees 58 



Insect injuries to the wood of living trees 60 



Insect injuries to the wood of dying and dead trees 62 



Insect injuries to forest products 64 



Insects in their relation to the reduction of future supplies of timber. . 67 



Interrelations of forest insects and forest fires 67 



Losses from forest insects 67 



Insect-killed timber as fuel for fires 68 



Fire-killed timber injured by insects 68 



Destruction of insects by fire 68 



Durability of insect-killed timber 69 



Interrelation of forest insects and forest fungi 69 



Decay following injury by insects 69 



Summary and estimates relating to character and extent of insect 



damage 69 



Standing timber killed and damaged by insects 70 



Reduction in the Nation's wealth 71 



Reduction in cash revenue 71 



Reduction in value of finished and commercial products 71 



Methods of prevention and control 71 



General principles of control 72 



Control of barkbeetles which kill trees 73 



Control of insects which cause defects in living timber 78 



Prevention of injury to dying and dead trees 78 



Prevention of loss from insect injuries to natural and artificial repro- 

 duction ''^ 



Prevention of insect injuries to forest products 79 



Utilization of natural enemies and factors in the control of injurious 



insects 85 



Utilization of waste caused by insects 87 



Present conditions and opportunities 88 



Forest entomology as applied to American forests 88 



Needs 89 



Elementary and technical knowledge of forest entomology for the 



forester 91 



Conclusion 91 



General estimates of amount of damage caused by forest insects 92 



How losses can be prevented 93 



Publications relating to forest insects 96 



Publications relating to forest statistics 100 



Index 103 



