LIBP A RY
STATE PLaANT BOARD
Issued March 7, 1911.
U. S. DEPARTMENT OF AGRICULTURE,
BUREAU OF ENTOMOLOGY-CIRCULAR No. 134.
L. 0. HOWARD, Entomologist and Chief of Bureau.
DAMAGE TO TELEPHONE AND TELEGRAPH
POLES BY WOOD-BORING INSECTS.
T. E. SNYDER,
Agent u id E.'pert.
WASHINGTON : GOVERNMENT PRINTING OFFICE : 1911
B UREA U OF ENTO MOLG)(FY.
L. 0. HOWARD, EnItomologist and C hief of Bureau.
C. L. MARLATT, Entomologist mnd Acting Chihf in Absence of ('hief.
R. S. CI.IFTO, Executive As.-sistant.
WV. F. TASTET, ('Chif Cc'rk.
F. H. (C'HITTENDEN, in charge of truck crop and stored product insect in rcstigations.
A. D. HOPKINS, in charge offorest insect inrestig(tions.
W. D. HUNTER, in charge of southern fietl crop insect inrestigations.
F. M. WEBSTER, in charge of cereal mid forage insect inrestigati;ns.
A. L. QUAINTANCE, in charge of decridiMuous fruit insect in restigations.
E. F. PHILLIPS, in charge of bhee culture.
D. M. ROGERS, in charge of prereniliniy sijrcad of moths, .fIeld work.
ROLLA P. CURRIE, in charge of ,i lorial work.
MABEL COLCORD, libralrifn.
FOREST INSECT INVESTIGATIONS.
A. D. HOPKINS, in charge.
H. E. BURKE, J. IL. WEBB, JOSEF BRUNNER, S. A. RoH\IV ER, T. E. SNYDER. WV. D.
EDMONSTON, W. B. TURNER, agents and experts.
MA'AiV E. I"AUNCE, preparat(ir.
\\II.iIAMI MIDDL.ETON, MARY C. JOHNSON, stludwcnt assistants.
CIRCULAR No. 134. Issue(l March 7, 1911.
United States Department of Agriculture,
BUREAU OF ENTOMOLOGY.
L. 0. HOWARD, Entomologist and Chief of Bureau.
DAMAGE TO TELEPHONE AND TELEGRAPH POLES BY
By T. E. SNYDER,
Agent ai.d E.rp ,'t.
It has recently been determined through special invest i6at ions con-
ducted by the Bureau of Entomolorgy, in cooperation with telephone
and telegraph companies, that serious and extensive damage is being
done in certain localities to standing pole- by wood-boring insects.
The object of this circular is to give information on the principal as
well as other types of insect injury to poles, so that line inspectors
may distinguish the various types and determine and report on the
character alnd extent of the damage.
CHARACTER OF TIIE INJURY.
The principal injury to the poles consists in large mines in the wood
near the line of contact with the ground, necessitating the frequent
resetting or even the replacement of the damaged poles. These
irregular mines. (fig. 1) run both transversely and longitudinally
throughout thle hiartwood, and are sometimes 7 inches long, but
vary in length. This injury is usually in the outer layers of tlhe
wood for a distance of from 2 to 3 feet below and sometimes from 1
to 2 feet above the line of contact of the pole with the surface of the
ground. The greatest damage is to that area just below and just
above the surface of the ground; here the conditions of air and
moisture are most favorable. The mines, often very close together,
completely honeycomb the wood in a zone from 3 to 4 inches in from
the exterior of the poles (fig. 3); this so weakens the poles that they
break off close to the surface of the ground. The basal 2 feet is
I RevLseI extracts from Bulkhtin 94, Part I, Bureau of Entomology, U. S. Department of Agriculture,
773.S--Cir. 134-11 1
STATE PLANT BOARD,
2 INSECT DAMAGE TO TELEPHONE AND TELEGRAPH POLES.
i,. i. -\\ork of the pole borer (',ti rmiti, briinna l'.iFj.) in an niiirc.iii chestnut pole: a, ( alh'rv of the
).il, borPr, -1IiI,, ii, pupal chI iiI),,r itIi th Iew 'IIir.tr.T iil ti, ,I '%l tIi e\11l-it-lik,- wood Ifibers; wOrk n-ar
e4eof I l below r',iiiiIl. b, Mwri s ,f the pole IlIirr near surface of LrMIiiil. N:l iIrilI siz.. ( Author's
ili, I I, iI )
INSECT DAMAGE TO TELEPHONE AND TELEGRAPH POLES. 3
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 commission; such
damaged poles are a serious menace along the right of way of rail-
roads. Poles that appear sound on the exterior may have tlhe
entire basal interior riddled, and the damage is not noticed until the
poles break off. If merely isolated poles are injured so as to caui:.
them to break off, they simply lean over, but if several adjacent poles
are affected, especially where there is any unusual strain, that por-
tion of the line is very likely to go down.
THE PRINCIPAL INJURIOUS SPECIES.
The principal injurious species is the chestnut telephone-pole
borer, or pole borer,1 which is an elongate, creamy-white, wrinkled,
Fl.1 2.-I, Thi. pole borer: Male and female beetles. ?, The pole borer: Young
larvwe. i, Sliiht ly riil rgc' I. 2, twice natural size. (Author's iillii i ial iin )
round-lleadled grub or larva (fig. 2,2). It hatches from an egg depos-
ited by an elongate, mah ogany-brown, slhiny, flattened, winged
beetle, from two-fifths to four-fiftlis of an inch in length (fig. 2, 1).
It appears that the eggs are deposited from August to October in
the outer layers of the wood of the pole near the surface of the
ground. The young borers, upon hatchling, excavate shallow gal-
leries in tlhe sapwood, then enter the heartwood, the mines being
gradually enlarged as they develop. As they proceed they closely
pack the fine boring dust behind them. This peculiar semidigested
boring dust, which is characteristic of their work, is reddish to dun-
I Parandra brunnea Fab. Since the ipublieiration of Bulletin 94, Part I, of this Bureau, this borer, first
found to be injurious to chestnut telephone pol,-. has been found injiirioijii to arborvitae poles, and as it
also injures telegraph poles, lh,. name "pole borer" is more appropriate and comprehensive.
4 INSECT DAMAGE TO TELEPHONE AND TELEGRAPH POLES.
nislh yellw in cob lr and has a clavlike consistency. The burrows
eventually end in a broad clhambl)er, thle entrance to which is plugged
with excelsiorlike fibers of wood. Here is formed the resting stage.
,r pupa, which transforms to the adult beetle. Often all stages, from
very young" grubs only about one-fourth inch long to full-grown
grubl)s over 1 inch long, pupZe, and adults in all stages to maturity
alre present in the same pole. Adults have been found flying from
July to September.
The insect attacks poles that are perfectly sound, but will work
wl here tlhe wood is decayed; it will not, however, work in wood that
is "sobby" (wet rot), or in very "doty" (punky) wood. It has not
yet )been determined just how soon the borers enter the poles after
tllthy have been set in tlhe gro:n'd. Ilowever, pcles that liad been
IF,. I -D).iniag,. toan untreated chestnut tthegraphi pole near .I-rf.,i.r of gxoril,,
1Y the pole borer. (Author's illustrationn)
standlinii only four or live years cont.aiiied larvae and adults of this
borer in the h1.irtwoood, and poles that liad been set in tlie ground
for only -wo ycnirs contaiined young larvia in the outer layers of tlie
for nytw es o .
The pr.''e'ne of thle b1)()rrs in injurious numnilbers can be deter-
min.e(I only 1by rcmovi-nI. the earth frinm al)ut thlie base of the pole;
tlie l:,iii' olls madle Nhlien t(he aldlilts come out are found near the
linfe of coIt % i
,dults nrn found on Ili, exterior of the p)les undervroi ind. Duringr
Aii,,,.t Ih ytie 1ou adults ny 1'be foi lud il shallow depr.essioins on the
(.xterior o,1" 1p,1o.-.le el,,w He .hr'oud s,,irfa c'.
INSECT DAMAGE TO TELEPHONE AND TELEGRAPH POLES. 5
INJURY BY OTHER INSECTS.
It is not to be concluded that injury by the pole borer is the only
type of insect damage to poles. Indeed, a very common injury is by
white ants, or termites. In lines from 10 to 12 years old serious
damage by these insects occurred in 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. The
damage, however, is usually to the outer layers of the wood, where it
is moist or there is incipient decay, and is more superficial and local-
ized than that of the pole borer. Nevertheless, the sound heartwood
of poles is often completely honeycombed, especially at the base. The
work of white ants is found both in sound wood, "doty" wood, and
"sobby" wood. Sometimes a large channel runs up through the core
of the heart and the sides are plastered with clay, forming a hollow
tube with several longitudinal interior galleries. Their work often
extends from 2 to 4 feet above the surface of the ground. They
leave the outer shell of the wood intact and work up through the
longitudinal weathering checks, covering the exterior of the pole with
earth to exclude the light. White ants will damage poles that have
been set in the ground only two years. Evidently they enter the
pole from below the surface of the ground.
Injury by a giant round-headed borer is sometimes found in chest-
nut poles. The large mines of this borer are found in the sound
and decayed wood of poles. Often where there is rot present the
lieartwood near the surface of the ground is completely honey-
combed by this borer.
Longitudinal weathering checks in chestnut poles are often widened,
and other defects enlarged by large, black carpenter ants and other
smaller black ants, which thus hasten decay.
KNOWN EXTENT OF THIE DAMAGE.
The pole borer has seriously damaged as high as 10 to 15 per cent
of the chestnut poles which have been set in the ground for from 10
to 12 years in lines in North Carolina, Virginia, West Virginia, Mary-
land, and the District of Columbia. It has only recently been deter-
mined that it has also seriously damaged a considerable proportion
of the arborvitae1 telephone poles in part of a line in Illinois. It is
evident, then, that this insect is an important factor in decreasing the
normal length of service of chestnut and arborvitae poles.
POSSIBILITIES OF PREVENTING DAMAGE TO POLES.
Methods of treating poles superficially by brushing with various
preservatives have proved to be temporarily efficient in keeping
out wood-boring insects, if the work is thoroughly done and not
1 Tli uja occidentalis.
6 INSEC-T DAMAGE TO TELEPHONE AND TELEGRAPH POLES. -
only the butt. but also the basal area, is treated. If the pole is not
thoroughlly brushed, the pole borer and other insects enter through the
untreated or imperfectly treated portions, especially through weath-
ering checks and knots. Where the base is left untreated, insects, .
especially white ants or termites, enter the pole from below ground
and, avoiding the treated portions, come right up through the pole. 0
Impregnating the poles with creosote by some standard process
(either by the open-tank or by a cylinder-pressure process) will keep
out wood-boring insects. In thie open-tank method only the area most
subject to the attacks of wood-boring insects (i. e., the basal 8 feet)
is treated, while by the cylinder-pressure processes the entire pole is
Therefore, to effectually protect poles from the depredations of
wood-boring insects it is recommended that they be impregnated with
creosote by either the "open-tank" process or by a cylinder-pressure
Approved: UNIVERSITY OF FLORIDA
11111111 IIII vi; 1111 illi li111II111 i 111111 IIII 11111 III lilt iiiI III 1IiI11 I Nl 1111 IU l
Secretary of Agriculture. 3 1262 09228 2796
WASHINGTON, D. C., January! 24, 1911.