Biology Reference
In-Depth Information
572
573
572
Web of
Yponomeuta cagnagella
on
Euonymus
.
573
Adult of
Yponomeuta cagnagella
.
574
larvae attacking the foliage to feed in communal webs
which eventually cover the shoots and branches of host
trees. Larvae are fully grown in June. They then pupate
in pendulous, semi-transparent, silken cocoons dispersed
throughout the communal web (cf.
Yponomeuta
evonymella
). Adults emerge a few weeks later.
DAMAGE
Host plants are disfigured by the presence of webbing
and loss or death of foliage; they are also weakened
following severe attacks. Large numbers of larvae and
pupae are often killed by parasitoids, but natural control
is often insufficient to prevent infestations from
reaching damaging levels.
574
Larva of
Yponomeuta cagnagella
.
Yponomeuta cagnagella
(Hübner) (
572-575
)
syn.
Y. cognatella
Treitschke;
Y. evonymi
Zeller
Infestations of this relatively common species occur on
wild European spindle (
Euonymus europaeus
) and are
also noted occasionally on cultivated spindle bushes.
The lifecycle is similar to that of
Yponomeuta padella
,
but larval activity commences slightly earlier in the
spring. At first, the larvae attack the unfurling leaves.
Later, they form conspicuous silken webs on the shoots
or branches. Adults (24-26 mm wingspan) are mainly
white, the fore wings with white cilia and four
longitudinal rows of black dots (including a row of 4-7
dots towards the lower margin). The larvae (18-22 mm
long when fully grown) are yellowish grey to greenish
grey, marked with black spots; head, prothoracic and
anal plates black; younger larvae are darker bodied.
Fully fed larvae pupate in groups in white, opaque
cocoons (cf.
Yponomeuta plumbella
). Adults emerge
in July.
575
575
Pupal cocoons of
Yponomeuta cagnagella
.
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