DAMAGE TO CHESTNUT POLES BY INSECTS. 7 
wood-boring insects except to that portion near the surface of the 
eround. Conditions of drainage are more important than different 
soil combinations, and the condition of the soil is more important 
than its composition; 7. ¢., where the soil is hard packed there is 
apparently less damage than where it is loose. The quality and con- 
dition of the poles before setting is a very important factor to con- 
sider before arriving at any conclusions as to the relative longevity of 
poles under various conditions of site. Green (unseasoned) or im- 
perfectly seasoned poles are less durable than those thoroughly 
seasoned. Poles that are defective * before setting, as they very 
often are (i. e., showing evidence of incipient decay), and poles that 
have the heartwood mined by the chestnut timber worm,? the work 
of which is very abundant, will, of course, decay much more 
rapidly than poles that are in an absolutely sound condition. 
The galleries of the chestnut timber worm afford an entrance to 
the spores of wood-destroying fungi, and thus greatly accelerate 
decay. White mycelium compactly filled these galleries throughout 
many standing poles, thus clearly proving that these mines aid 
ereatly in enabling the fungous’ heart rot more rapidly and 
completely to penetrate the entire heartwood of the poles. If the 
injury by both wood-boring beetles and wood-destroying fungi 
(between which there is a varying interrelation) be considered, then 
in several lines from ten to twelve years old in North Carolina,. 
Virginia, and West Virginia at least 50 per cent of the poles are either 
rendered unserviceable or their length of service is much shortened. 
ASSOCIATED WOOD-BORING INSECTS. 
It is not to be concluded that this wood-boring beetle is the only 
insect that injures standing chestnut poles. Indeed, the most 
common injury is by the “wood lice” or white ants.° In lines from 
ten to twelve years old these insects have seriously damaged as high 
as 15 per cent of the poles, and their work is often present, at least 
superficially, in as high as 75 per cent of the poles under all conditions 
of site. However, the damage is usually to the outer layers of the 
wood, where it is moist or there is incipient decay, and is more 
superficial and localized than that of the chestnut telephone-pole 
borer. Nevertheless, white ants often completely honeycomb the 
sound heartwood of poles, especially at the base. They work both 
in sound wood, “doty” (dry rot) wood, and “sobby”’ (wet rot) wood. 
Sometimes a large channel runs up through the core of the heart 

4QOften this evidence is the old galleries of the destructive two-lined chestnut 
borer (Agrilus bilineatus Web.), showing that the tree must have been dead before 
it was cut for a pole, and hence is more likely to be defective throughout the interior; 
in other instances heart rot is clearly present. 
6 Lymexylon sericeum Harr. 
¢ Identified by Mr. Theodore Pergande of this Bureau as Termes flavipes Kollar. 
