Biology Reference
In-Depth Information
DAMAGE
Infested shoots and branches may be weakened, but
infestations are localized and generally of only minor
significance.
LIFE HISTORY
Infestations occur on the foliage and shoots throughout
the year with, in suitably warm conditions, a succession
of generations annually. Elsewhere, there is just one
generation annually, immature scales overwintering and
the characteristic ovisacs being produced in April and
May soon after mating has occurred. Mature females
perish soon after completing their ovisacs and laying
eggs, and fall away from the host plant before the eggs
hatch.
Chloropulvinaria floccifera
(Westwood) (
210
)
syn.
Pulvinaria floccifera
(Westwood)
Cushion scale
An often common pest of greenhouse-grown
Camellia
and orchids; in favourable areas, infestations also
occur outdoors. Other hosts include
Citrus
, holly
(
Ilex
), Japanese spindle (
Euonymus japonica
) and
Rhododendron
. Probably of southern European origin
but nowadays found in many parts of the world.
Widespread in Europe.
DAMAGE
Attacked plants are often disfigured by accumulations
of flocculent waxen 'wool'.
Coccus hesperidum
Linnaeus (
211
)
Brown soft scale
A very common, polyphagous and virtually worldwide
pest of greenhouse ornamentals; also attacks outdoor
plants growing in favourable situations, including many
parts of mainland Europe and southern England.
Commonly infested hosts include azalea
(
Rhododendron
), bay laurel (
Laurus nobilis
),
Camellia,
Citrus, Clematis, Escallonia, Geranium, Hibiscus
, holly
(
Ilex
), ivy (
Hedera
), oleander (
Nerium oleander
),
poinsettia (
Euphorbia pulcherrima
),
Stephanotis,
Viburnum
, weeping fig (
Ficus benjamina
) and various
ferns.
DESCRIPTION
Female scale:
2.5
2.0 mm; oval and yellowish,
surmounting an elongate (10-15 mm long), thin, white
ovisac.
Egg:
minute, oval and pinkish.
×
210
DESCRIPTION
Female scale:
3.5-5.0 mm long; very flat and oval;
translucent yellow to brown, with an often distinct
median longitudinal ridge and rib-like markings.
LIFE HISTORY
This species is viviparous, and usually parthenogenetic,
each female producing about a thousand nymphs over a
period of 2-3 months. The first-instar nymphs wander
over host plants for a few days before settling down to
feed on the leaves, with individuals clustered along the
midrib and other major veins; the insects often overlap
one another, forming dense (often ant-attended)
colonies. Breeding is continuous, so long as conditions
remain favourable, and the complete lifecycle from
birth to maturity occupies about two months at average
greenhouse temperatures.
210
Cushion scale (
Chloropulvinaria floccifera
).
211
DAMAGE
The scales excrete considerable quantities of honeydew,
and foliage beneath infested leaves becomes extensively
blackened by sooty moulds. This spoils the appearance
of ornamentals and checks growth.
211
Colony of brown soft scale (
Coccus hesperidum
).
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