The apple tree borers have destroyed thousands of trees in New
England, and are likely to destroy thousands more. There are three
kinds of borers which assail the apple tree. The round headed or two
striped apple tree borer, _Saperda candida_, is a native of this
country, infesting the native crabs, thorn bushes, and June berry. It
was first described by Thomas Say, in 1824, but was probably widely
distributed before that. In his "Insects Injurious to Fruit," Prof.
Saunders thus describes the borer:
"In its perfect state it is a very handsome beetle, about
three-quarters of an inch long, cylindrical in form, of a pale brown
color, with two broad, creamy white stripes running the whole length
of its body; the face and under surface are hoary white, the antennæ
and legs gray. The females are larger than the males, and have shorter
antennæ. The beetle makes its appearance during the months of June and
July, usually remaining in concealment during the day, and becoming
active at dusk. The eggs are deposited late in June and during July,
one in a place, on the bark of the tree, near its base. Within two
weeks the young worms are hatched, and at once commence with their
sharp mandibles to gnaw their way through the outer bark to the
interior. It is generally conceded that the larvæ are three years in
reaching maturity. The young ones lie for the first year in the
sapwood and the inner bark, excavating flat, shallow cavities, about
the size of a silver dollar, which are filled with their sawdust-like
castings. The holes by which they enter being small are soon filled
up, though not until a few grains of castings have fallen from them.
Their presence may, however, often be detected in young trees from the
bark becoming dark colored, and sometimes dry and dead enough to
crack."
On the approach of winter, it descends to the lower part of its
burrow, where it remains inactive until spring. The second season it
continues its work in the sapwood, and in case two or three are at
work in the same tree may completely girdle it, thus destroying it.
The third year it penetrates to the heart of the tree, makes an
excavation, and awaits its transformation. The fourth spring it comes
forth a perfect beetle, and lays its eggs for another generation.