a temporary nature, and often have been impractical in application. As in 

 the case of subterranean termites, recent development of new insecticides 

 and wood preservatives gives considerable promise of more effective and 

 permanent control. The;e is much yet to be lenrned about the methods to 

 use in obtaining penetration of residual insecticides into the wood in 

 order to control active infestations and to prevent future attack. In 

 localities where the problem is particularly severe, preventive treatments 

 of a permanent nature may be applied to all wood used in new construction 

 or for replacement purposes. 



Wood Borers 



Several species of vrood-boring beetles, including largely the rrroups known 

 as wood borers and the powder-post beetles, present special problems in the 

 deterioration of wood in v/aterfront structures. Some may attack wood in 

 the green log stage, or the green lumber upon which bark flitches remain. 

 They may survive air-drying treatment and, if the vrood is utilized within 

 one or t/o years, will continue their activities ,ithin structures, Iiost 

 of the species complete their development frora v/orms or larvae to adults 

 within 2 years, emerge, and never reattack. A few .rill re infest the wood 

 and continue their destructive activities indefinitely, Tiile the extent 

 of damage caused by this group of insects is not well known, it nevertheless 

 creates undesirable problems. Emerging borers make holes from 1/8 to l/ii 

 inch in diameter in the surface of the wood containing them, and if panel- 

 ing, wall board, flooring, or other material is laid over this wood, they 

 will bore through it also in order to emerge. 



By far the most destructive beetles are those classed broadly as powder- 

 post beetles v/hich attack seasoned vrood. These attack the wood directly 

 either during storage on the lumber yard or in a structure and continue 

 their activities, breeding one generation of pro'Sieny after another until 

 the Y\rood is completely destroyed. Some damage wood rapidly, others slowly 

 but surely, jMle most of the species are of world wide distribution, 

 only a fevr have been studied sufficiently to determine their habits and 

 control. 



The group known as Lyctus powder-post beetles has caused concern in the 

 wood-using industry for many jrears. This tiny black or brovm hard-shelled 

 insect attacks principally the large-pored hardwoods such as oak, hickory, 

 ash, walnut, etc. Thile the green wood ro,ay be attacked in the lumber yard, 

 it is usually the finished product that is infested, and destruction is 

 greatest when products are in storage. It is impossible to estimate 

 accurately the total amount of destniction caused by these beetles to floor- 

 ing, wood gunstock blanks, cots, furniture, tool handles, dunnage, and other 

 items in this country alone. It is equally severe in other parts of the 

 world and several countries have recognized the problem to the extent that 

 legislation has been employed in an effort to prevent serious losses and 

 keep the insects under control, 



Another powder-post beetle knovm v/idely for its destructive activities and 

 one which is becoming increasingly important is the old house borer or 



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