DEFECTS IX TIMBER CAUSED BY IXSECTS 



35 



The burrows are tightly packed with pellets of excrement, and 

 shingle stock is full of holes. (Fig. 27.) 



The injury occurs in living, dying, or dead trees, and consists of 

 a flattened, oval, gradually enlarging, more or less tortuously winding 

 mine or wormhole, which, when completed, widens out into an 

 elongate-oval pupal cell. This cell connects with the outer surface 

 by a short, oval exit hole. The mine has its surface marked by fine 

 transverse, crescentic lines, and is usually tightly packed with saw- 

 dustlike borings and pellets of woody excrement. 



To prevent such injury, the forest should be kept clear of dead 

 and dying trees and of felled trees which afford ideal breeding 

 spots. Such trees might be used for fuel, or they could be piled 

 with the limbs and tops 

 and burned. If trees 

 must be deadened in 

 the lumbering opera- 

 tions, the " deadening " 

 should be done at a 

 time of the year when 

 the sap is not actively 

 flowing. October, No- 

 vember, and December 

 would probably be the 

 best months for this. 

 If the timber must be 

 felled and left in the 

 woods for a time, the 

 felling should be 

 done during the same 

 months, and the logs 

 should be barked and 

 left so that they will 

 dry quickly and thus 

 become distasteful to 

 these borers. 



If the timber is 

 found to be newly in- 

 fested while standing, 

 or on felling, the most 

 practical remedy is to cut it into logs at once and place the logs 

 in a pond or stream so that the larvae will be destroyed and 

 further damage prevented. If the damage has been done before 

 the lumberman has noticed the injury, which is usually the case, 

 much loss can often be prevented by utilizing the damaged stock 

 to the best advantage. It may be used for poles, posts, plank- 

 ing, sills, small construction timbers, or where the wormholes are 

 not particularly detrimental; it should not be used for cooperage, 

 shipbuilding, shingles, doors, finishing, cabinetmaking, or furniture, 

 in which clear stock is desired : otherwise the loss is apt to be severe, 

 both because of the poor quality of the product and because of the 

 extra labor necessary to produce it (7). 



Fig. 3S. — Longitudinal section of yellow pine sapling, 

 snowing damage to wood from attack of Pinipestis 

 zimmermaniii. (.0) 



