THE PEACH-TREE BORER 
Bij Wilbur C. Gillesjne under the direction of J. P. 
Stewart, Pennsylvania Stale College 
The peach-tree borer is the larval stage ol a bluish 
green, wasp-like moth which is rarely seen by the or- 
chardist, since it is shy in its habits and very ineonspic- 
nons. The adult moths emerge in Pennsylvania from 
about June 15 to September 15, the majority appearing 
fi'om July 1 to August 15. Mating takes place at once, 
and the females under ordinary conditions oviposit on 
the truidvs of the peach trees just at the surlace of the 
ground. Each female lays from 200 to 600 eggs, which 
are n'ddish-hrowii in color, about one-fiftieth of an inch 
in length, and slightly llattened on the sides. In 9 or 10 
days the young lai'vac hatch and begin at once to burrow 
into the soft wood of the peach trees. The partly grown 
lai-va(‘ stop burrowing with the api)roach of cold weather 
and lie dormant over winter just beneath the bark or 
sometimes beneath small silken webs on the outside of 
the bark. 
With the coming of spring they resume their tunneling, 
the greatest damage being dom; from that time until their 
full growth is attained, which is, in general, from the lat¬ 
ter i)art of May to July 15. When full growm the laiwae 
stop feeding and form small brown cocoons composed of 
silk intermingled wdth bits of bark and excrement. These 
are usually attached to the tree near the surface of the 
ground, although they may often be found lying in the 
soil near the base of the tree. Within these cocoons the 
laiwae transform to pupae in about four days, and after 
a pupation period of 3 or 4 weeks the adult moths emerge. 
This performance completes the life cycle which covers 
nonnally a period of one year. 
Character of Injury. The injury caused by peach- 
tree borers is due to the tunneling beneath the bark by 
the larvae. Young trees in the nursery row may be com¬ 
pletely girdled and killed by a single borer. Mature trees 
are much better able to withstand the attacks, although 
the great number of borers often found in old trees 
usually more than makes up for the increased resistance 
of the trees. The w ork of the borers is usually confined to 
the area included w ithin a few" inches above and below 
the surface of the ground. Masses of gummy material 
intermingled with woody castings on the tree trunks just 
at the surface of the ground and a generally sickly ap¬ 
pearance of the foliage are sure indications of their pres¬ 
ence. Borers are never of any benefit to the tree, and the 
burrow ing of only one or twm is a considerable drain on 
the tree’s vitality. 
Control Measures. After the borers have become es¬ 
tablished in the trees, no treatment except digging them 
out with a sharp knife and a piece of pliable w ire is prac¬ 
ticable. on a large scale at least. The use of carbon bi¬ 
sulphide. potassium evanide and similar materials to 
kill the 1 xtnu's in their tunnels was formerly advocated. 
It is now g(‘n(‘rally recognized that these materials are 
practically valiieh'ss for this purpose, due to the fact that 
the timiH'ls ar(‘ solidly filled w ith gummy material which 
acts as an ('ffective harrier to poisonous fumes. 
Doctor Smith of the \ew" Jersey Station stated in a bul¬ 
letin published several years ago that where only a few" 
trees are to be treated for borers hot water at a tempera¬ 
ture of not over 175 degrees, applied about the crowns 
occasionally, w"ill serve to keep them free from borers, 
provided the exudations of gum are first removed. Ihis 
treatment belongs in the distinctly doubtful class, though 
it might be tried on a few" trees, and the effects on both 
the borers and trees carefully noted. 
Finding a material for use as a protective coating on 
the trunks with the object of keeping the borers out has 
attracted the attention of many experimenters and peach 
grow ers. The ideal material for this purpose would be 
one whicb would keep the borers out, not injure the trees, 
not be expensive, and w ould be elastic enough and adhere 
to the trees w ell enough so that one good application an¬ 
nually would maintain a good coating. Many protective 
coatings have been recommended by different stations. 
So far, no one of them can be unqualifiedly recommended 
on account of the fact that the results reported from their 
use have been so conflicting that no definite conclusions 
can be reached as yet. Some of the materials give prom¬ 
ise of being of value, others have been found worthless, 
and still others have been proved to be actually injurious. 
Of the materials tested at other stations, white lead and 
linseed oil, hydraulic cement wash, Hale’s wash, and gas 
tar have been reported promising by one or more. Ex¬ 
periments carried on by the Pennsylvania Station from 
1909 to 1912 have shown that white lead and oil paint is 
not safe on peach trees, and that ordinary cement coatings 
flake off too quickly to be of any practical value. In the 
case of the gas tar treatment, the Cornell Station found it 
to be the most satisfactory of any tried in an extensive 
test of different materials for use as washes, while in 
Missouri serious damage to the trees has invariably been 
reported from its use. 
Whitewash, pine tar, tallow, and asafetida are some of 
those which may be classed as useless, and in the case of 
the tar, at least, dangerous. Washes containing paris 
green in large (luantities, printer’s ink, rubber roofing ce¬ 
ment, and creosoting oil are some of those which have 
been found to be dangerous to use on account of almost 
certain injury to the trees. 
Mechanical protectors of various kinds are sometimes 
recommended, Imt in general they have proved too expen¬ 
sive to maintain for use on an extensive scale. Further¬ 
more, very few" of them have been at all satisfactory. 
Wire cages, w"hich theoretically should give perfect pro¬ 
tection, seemed actually to attract the borers, according 
to results obtained from their use at the Cornell Station. 
Common paper protectors require too much care in keep¬ 
ing them adjusted to be practical. Tar paper has been 
know"n to cause injury to the trees through making the 
bark soft and tender, also on account of the promotion of 
sun scalding due to absorption of heat. Tobacco stems 
w"ound about the trees and tied have given fairly good 
protection, but the chief difficulty in their use lies in the 
fact that the strings binding them in place are likely to 
cut the trees, hence they require more care than is jus¬ 
tifiable. 
A new" form of tree protector for the control of borers 
has recently appeared on the market. It consists of a 
flexible mat of tar paper which encircles the tree and a 
paste for sealing the mat to the tree. The protector has a 
