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Description
The small, reddish, adult European and Nantucket pine moths are
not likely to be seen, but their larvae or pupae may be found in
damaged buds and shoots. The mature larvae of the European pine
shoot moth are about 5/8 inch long and have brownish bodies
and black heads. The mature larvae of the Nantucket pine tip
moth are about 3/8 inch ling and have yellowish bodies and brown
heads. The pupae of both are dark brown and slightly smaller than
their respective larvae. The adult Zimmerman pine moth is
gray with a mottled forewing of red and gray. The mature larvae
are pink to green, depending on the host, with black spots containing
a single bristle each. The mature larvae are about 3/4 inch long.
Life
History
The European pine shoot moth overwinters in the larval stage
in the buds of pines. The larvae resume feeding in the spring, complete
their development, and pupate. The moths emerge in June to deposit
eggs. The Nantucket pine tip moth, on the other hand, overwinters
in the pupal stage in the pine twigs. Moths begin to emerge in April
to deposit eggs, and they continue to emerge through May. Both of
these insects lay flat, inconspicuous eggs on the needles as well
as into the buds and shoots. There is only one generation of the
European pine shoot moth per year, but there may be two or more
generations of the Nantucket pine tip moth in a year.
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Zimmerman pine moths deposit eggs in mid-August on
the bark near the edge of wounds. The larvae hatch in about
2 weeks and spin hibernaculae. Activity resumes the following
spring with feeding beginning in May or June. The larvae first
feed on the bark and then bore into the cambium, causing the
terminals'to turn yellowish-green with extensive accumulations
of frass and resin at the crotch of the branch. In late June,
the larvae tunnel beneath the bark in the whorl area and later
pupate within the resin mass. There is one generation per
year.
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Click on image for larger
version
Figure 1. Zimmerman Pine Moth Adult
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Damage
The European pine shoot moth is mainly a pest of Scotch,
mugho, and red pine in northern Illinois. Pitch at the bud and a
few dead needles with webbing are the first indication of an infestation.
Larval feeding stunts the twigs ("shepherd's crook") and
causes deformed and bush growth. Crooked stems called "post
horns" result when a damaged shoot recovers. Injury caused
to a bud or shoot by the European pine shoot moth is almost invariably
the work of a single larva.
The
Nantucket pine tip moth is a pest of loblolly and shortleaf
pines, especially those in the southern half of Illinois. Larval
feeding kills the shoots, each of which may have several entrance
holes with pitch flowing out. Damage may be extensive and, depending
on the degree of, infestation, either severe or light. Injury by
the Nantucket moth pine tip moth is usually the work of several
larvae.
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Click on image for larger
version
Figure 2. Zimmerman Pine Moth Damage
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The
Zimmerman pine moth is a pest of most pine species,
with Scotch and Austrian pines being very susceptible. The
larval tunneling will girdle branches and leaders and cause
dieback.
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