INSECT INJURIES TO FOREST PRODUCTS, 



By A. D. HOPKINS, 



In Charge of Forest Imect Investigations, Bureau of Entomology. 



CHARACTER AND EXTENT OF INJURY. 



The detrimental and destructive work of insects which cause serious 

 losses in commercial woods, barks, nuts, etc., consists of burrows or 

 galleries excavated by the young and matured forms of beetles and a 

 few other kinds of insects. 



Round timber, rough lumber, and other crude products are seriously 

 injured by pinhole and wormhole defects caused by a class of wood- 

 >ring beetles and grubs. v 



Seasoned rough and dressed lumber and finished wood material is 

 laged or completely destroyed by a class of so-called powder post 

 >rcrs. which convert the woody tissue into a mass of fine dust or 

 >wder. 



Construction timbers and other wood material utilized in buildings, 

 >ridges, railroad construction, mining, etc., are often infested by 

 rood-boring grubs, powder post borers, white ants, and other insects, 

 their serious detriment or destruction. 



Stored oak and hemlock bark for tanning purposes is, under certain 

 mditions, seriously damaged or destroyed by insects which infest 



inner or "flesh" parts and convert them into a fine powder. 

 Medicinal barks, roots, and leaves are also bored or eaten by drug 

 ietles, causing injuries which, while not necessarily destroying the 

 ledicinal qualities, are detrimental to the commercial value of such 

 laterial. 



From the writer's personal investigations of this subject in different 

 5tions of the counhy, the damage to forest products of various kinds 

 >m this cause seems to be far more extensive than is generally recog- 

 lized. Allowing a loss of 5 per cent on the total value of the forest 

 )ducts of the country, which the writer believes to be a conservative 

 jtimate, it would amount to something over $30,000,000 annually, 

 lis loss differs from that resulting from insect damage to natural 

 >rest resources in that it represents more directly a loss of money 

 ivested in material and labor. 



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