DAMAGE TO CHESTNUT POLES BY INSECTS. 



3 to 4 inches in from the exterior of the poles; this so weakens the 

 poles that they break off close to the surface of the ground. The 

 basal 2 feet is usually sound. Even if the damage is not serious 

 enough to cause the poles to break off under strain, they are likely to 

 go down during any storm, and thus put the wire service out of com- 

 mission; such damaged poles are a serious menace along the right of 

 way of railroads. The beetle will attack poles that are perfectly 

 sound, but evidently prefers to work where the wood shows signs of 

 incipient decay; it will not work in wood that is "sobby" (wet rot), 

 or in very "dotyV (punky) wood. It has not yet been determined 

 just how soon the borers usually enter the poles after they have been 

 set in the ground. However, poles that had been standing only four 

 or five years contained larvae and adults of this borer 

 in the heartwood, and poles that had been set in the 

 ground for only two years contained young larvae in the 

 outer layers of the wood. 



Poles that appear sound on the exterior may have the 

 entire basal interior riddled, and the work of the borers 

 is not noticed tmtil the poles break off. If merely iso- 

 lated poles are injured, the poles that are broken off are 

 held up by the wires and can be detected by the fact 

 that they lean over, but if several adjacent poles are 

 affected, especially where there is any unusual strain, 

 that portion of the line is very likely to go down. The 

 presence of the borers in injurious numbers can be de- 

 termined only by removing the earth from about the 

 base of the pole; the exit holes of the borer are found 

 near the fine of contact with the soil. Often large, 

 coarse borings of wood fiber project from the exit holes. 

 Sometimes old dead parent adults are foimd on the 

 exterior of the poles underground. During August the 

 young adults may be found in shallow depressions on the exterior of 

 poles below the ground surface. 



Fig. 3. — The 

 chestnut tele- 

 phone-pole bor- 

 er : Pupa. 

 Slightly more 

 than twice 

 natural size. 

 (Original.) 



IMPOBTANCE OF THE PROBLEM. 



The subject of the relation of insects to the rapid decay of chestnut 

 poles has not been thoroughly investigated in the past, but now that 

 the supply is becoming scarcer it is especially important to know 

 what are the various primary causes of the deterioration of these 

 poles, hitherto described under the vague term "decay." Although 

 the chestnut telephone-pole borer has not hitherto been considered an 

 insect of any economic importance, and has been described in ento- 

 mological literature as only living under bark, principally of pine, or 



