Biology Reference
In-Depth Information
232
233
232
Long-tailed mealybug (
Pseudococcus longispinus
).
233
Colony of root mealybug (
Rhizoecus falcifer
) on roots
of
Lavendula
.
Family
MARGARODIDAE
Pseudococcus longispinus
(Targioni-
Tozzetti) (
232
)
Long-tailed mealybug
Infestations of this common glasshouse mealybug often
occur on cacti, lilies, orchids, vines and many other
ornamentals. Individuals are relatively small (adults,
c
. 2.5 mm long), with very long caudal processes.
Colonies produce considerable quantities of honeydew.
A small group of mainly tropical insects; females
typically mobile, with well-developed legs and 6- to
13-segmented antennae.
Icerya purchasi
(Maskell) (
234
)
Cottony cushion scale
Originally an Australian species, now a serious pest of
citrus plants in various parts of the world; infestations
also occur on ornamentals such as
Acacia
, broom
(
Cytisus
),
Mimosa
and rose (
Rosa
). Attacks are common
in citrus-growing regions of southern Europe, and
may also occur occasionally on greenhouse-grown
ornamentals and house plants further north. Females are
about 5 mm long, brown and oval, each surmounting a
large (
c
. 10 mm long), white, distinctively grooved
ovisac which contains several hundred eggs.
Rhizoecus falcifer
(Künckel de Herculais) (
233
)
syn.
R. terrestris
(Newstead)
Root mealybug
Dense subterranean colonies of this and certain other
closely related species often develop on the roots of
(mainly) greenhouse-grown ornamentals, surrounded
by fragile masses of white wax. In common with
container-grown plants infested with root aphids, the
colonies often occur at the periphery of the root ball.
The mealybugs are elongate (1.0-2.3 mm long), with
distinct, 5-segmented, geniculate antennae and a pair of
very short, waxy anal appendages; although greenish
yellow, the insects appear white due to the mealy
coating of wax. Reproduction is parthenogenetic, the
mature females depositing their white, translucent eggs
in batches inside cottonwool-like ovisacs; there is a
succession of generations throughout the year. The
foliage of attacked plants becomes dull, heavily infested
plants making poor growth and eventually wilting.
234
234
Cottony cushion scale (
Icerya purchasi
).
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