Biology Reference
In-Depth Information
556
Argyresthia thuiella
(Packard) (
556-557
)
American thuja shoot moth
larva
American thuja leaf miner
A North American pest of Cupressaceae, especially
Lawson cypress (
Chamaecyparis lawsoniana
) and
white cedar (
Thuja occidentalis
); accidentally
introduced in the late 1970s into parts of mainland
Europe, including Austria, Germany and the
Netherlands, where it is now well established. Reports
of this species attacking juniper (
Juniperus
) are due to
confusion with
Argyresthia trifasciata
.
=
DESCRIPTION
Adult:
8 mm wingspan; head and thorax whitish; fore
wings white to greyish white, with silver-grey
markings.
Egg:
greenish.
Larva:
up to 5 mm long;
body green or brownish, often with a reddish tinge at the
posterior margin of each segment; head and prothoracic
plate shiny black or brown.
Pupa:
3.5 mm long; green
to brown.
556
American thuja shoot moth (
Argyresthia thuiella
).
557
LIFE HISTORY
Adults occur mainly in late June and July, when they
may be found settled on the foliage of host plants; if
disturbed, they fly a short distance before resettling.
Eggs are laid between scales, and hatch in 2-3 weeks.
The larvae then bore into the shoots to begin feeding,
each mining away from the tip. Larval development
continues from July onwards, and fully grown
individuals eventually pupate in the following May or
June.
557
American thuja leaf miner (
Argyresthia thuiella
) damage
to shoot of
Thuja
.
DAMAGE
Tips of mined shoots become discoloured, and
eventually turn brown and die.
558
Argyresthia trifasciata
(Staudinger) (
558
)
A common pest of juniper (
Juniperus
) in southern
Europe. In recent years it has greatly extended its range
and is now found in many countries, including Austria,
Belgium, Britain, the Czech Republic, Denmark,
France, Germany, Italy, the Netherlands, Poland,
Sweden and Switzerland. The pest also occurs on
Chamaecyparis
,
Cupressocyparis
,
Cupressus
and
Thuja
.
DESCRIPTION
Adult:
10 mm wingspan; fore wings blackish, each
marked with whitish crosslines; hind wings dark grey.
Larva:
up to 5 mm long; greenish, with a blackish head.
558
Argyresthia trifasciata
damage to shoot of
Juniperus
.
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