POWDER-POST DAMAGE BY LYCTUS BEETLES ' TO 

 SEASONED HARDWOOD. 



Page. 



Evidence of attack and character of powder- 

 post injury 4 



Classes o f forest product s damaged 4 



Extent of losses, and those upon whom they 

 fall ". 7 



Character of the insects which cause the dam- 

 age >< 



Page. 



Habits and seasonal history of Lyctus beetles. 8 

 The four species responsible for most of the 



losses 12 



Conditions favorable for attack 15 



Conditions unfavorable for attack 15 



Insect enemies of Lyctus beetles 17 



Methods of control 18 



The sapwood of seasoned hardwood material of all kinds, both 

 finished and unfinished, especially of hickory, ash, and oak, is often 

 ruined by yellowish-^Yhite grubs from one-eighth to one-fifth inch 

 in length which burrow through the solid wood in all directions and 

 convert it into powder. These grubs are the young, or larvae, of 

 small, slender, somewhat flattened, reddish-brown to nearly black 

 beetles, known as powder-post beetles. Wood that has been seasoned 

 a year or longer is especially liable to this peculiar type of insect 

 injury, which sometimes amounts to from 10 to 50 per cent of 

 neglected material in storage. Powder-post damage by these beetles 

 is w^idely distributed over the Avorld and the consequent losses have 

 been severe. 



Under the general class of powder-post injury the work of insects 

 representing several species and groups of species of beetles may be 

 found, but by far the larger part and the most serious damage and 

 losses are caused by different species of Lyctus. 



1 The Lyctus beetles which are responsible for the principal losses belong to four species, 

 viz, Lyctus linearis Goeze, L. planicolUs Le Conte. L. pornllelopipedus Melsheimer, and 

 L. cavicollis Le Conte. These are discussed separately on pages 12-15. 



Note. — Systems of control which adapt certain features in business management to the 

 habits and seasonal history of Lyctus powder-post beetles have been perfected by the 

 Bureau of Entomology and have been adopted by many manufacturers and dealers in 

 seasoned hardwood products, and there has been a nr.arked decrease in powder-post losses 

 since 1906. The object of this bulletin is to describe the methods which have been found 

 effective in preventing these losses and to induce a more general adoption of them through- 

 out the United States as well as to show the character and extent of the damage. 



3 



