Biology Reference
In-Depth Information
943
Family
DIPRIONIDAE
Slow-moving, stout-bodied sawflies, the males with
antennae strongly bipectinate; antennae of females
distinctly toothed. Larvae are associated with
coniferous plants.
Diprion pini
(Linnaeus) (
943-944
)
Pine sawfly
A locally common pest of pine (
Pinus
), sometimes
associated with ornamentals. Widely distributed in
central and northern Europe.
DESCRIPTION
Adult female:
10 mm long; head and thorax mainly
dark brown; abdomen pale yellowish brown, marked
with black; antennae serrated.
Adult male:
8-9 mm
long; blackish brown, with partly paler legs.
Larva:
up
to 25 mm long; head brown; body pale yellowish to
yellowish green, but darker dorsally, with a row of black
spots along each side.
943
Female pine sawfly (
Diprion pini
).
944
LIFE HISTORY
Adults are active in May or June. Females eventually
deposit rows of eggs in slits made in the previous year's
needles. Larvae emerge 2-3 weeks later and then feed
communally on the needles. If disturbed, members of
the colony adopt a threatening posture, grasping the leaf
edge with the thoracic legs and extending the abdomen
upwards in the shape of an 'S'. The larvae are fully fed
in July. They then spin cocoons on the host plant or on
the ground. A second generation of adults appears in late
July or August. Larvae of this generation feed during the
later summer; in September or early October, when
fully grown, they enter the soil or leaf litter to spin
cocoons. Pupation occurs in the following spring.
944
Larva of pine sawfly (
Diprion pini
).
DAMAGE
Larvae devour the needles and may also browse on the
bark of the young shoots. Attacked shoots are often
stripped of needles, and small trees may be completely
defoliated.
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