DEFECTS I2T TIMBER CAUSED BY INSECTS 



33 



stock, all the bark and edgings should be removed; treatment with 

 shellac or wax will also prevent the adult beetles from boring into 

 the wood to lay eggs. 



POWDER POST CAUSED BY ROUND-HEADED BORERS (CERAMBYCIDAE) 



Holes about one-eighth of an inch in diameter, tightly packed 

 with finer frass, in the sapwood or heartwood of oak and hickory, 

 are made by the flat 



i*yf 



'j*PW|L 



powder-post beetle. 25 It 

 attacks both freshly cut 

 and seasoned timbers 

 and continues to work 

 for a number of years. 

 Damage can be pre- 

 vented by prompt han- 

 dling of the logs, re- 

 movel of the bark, and 

 disposal of infested 

 stock. 



Oval holes about one- 

 fourth of an inch in 

 diameter or irregular 

 burrows tightly packed 

 with coarse, powdery 

 frass, in the heartwood 

 and sapwood of ash, 

 are caused by a round- 

 headed borer. 26 (Figs. 

 33 and 34.) This in- 

 sect attacks only freshly 

 cut timbers, but when 

 infested logs are stored 

 the borers continue to 

 work for several j 7 ears 



Prompt utilization, 

 submerging the logs in 

 the mill pond, rapid 

 seasoning, or removal 

 of the bark will pre- 

 vent this defect. Tim- 

 ber should be felled in 

 the late fall or winter, 

 so that the bark may 

 dry somewhat and be 

 less attractive to the 

 beetles when they are flying and depositing their eggs early in 

 the spring. In the Gulf States logs should not be allowed to 

 lie in the woods at any time for more than two to three weeks, 

 or after the 1st of April farther north, nor should they be 



"*1 .«"•*. 



— 



; 



Fig. 36. — Ring distortions in balsam caused by tbe 

 spruce bud worm. Base of tree attacked in 1911 

 showed accelerated growth for two years, followed 

 by retardation and incomplete ring in 1918 (X), and 

 rapid recovery later. (J/S) 



S modicum cuciijiforme Say. 



-' 6 Xcoclytus capraea Say. 



