Biology Reference
In-Depth Information
Family
COCCIDAE
(soft scales)
there may be two generations annually; elsewhere, there
is just one. The winter is usually passed as second-instar
nymphs.
Body of female forming a smooth or wax-covered, often
tortoise-shaped, scale. Pupal covers of males are known
as 'tests'. As in the previous family, first-instar nymphs
are often known as 'crawlers'.
DAMAGE
Infested hosts are weakened, and heavily infested leaves
and shoots may be killed. In addition, sooty moulds
developing on honeydew excreted by the pest reduces
photosynthetic activity of the leaves.
Ceroplastes rusci
(Linnaeus) (
208
)
Fig wax scale
A polyphagous pest of common fig (
Ficus carica
),
common myrtle (
Myrtus communis
), oleander (
Nerium
oleander
),
Pittosporum
and various other plants. Of
Chinese origin; now widely distributed in the
Mediterranean basin, including southern Europe.
Ceroplastes sinensis
del Guercio (
209
)
Citrus wax scale
This minor pest, of Chinese origin, is well established in
various Mediterranean areas, including France, Italy
and Spain, where it is associated mainly with plants
such as Brazilian peppertree (
Schinus molle
),
Citrus
,
Japanese holly (
Ilex crenata
),
Rhus
and ornamental
Solanum
.
DESCRIPTION
Adult female (scale):
up to 5 mm long; barnacle-like,
formed from eight fused plates; whitish-marble,
variably marked with brown.
Male test:
2.0-2.2 mm
long; reddish.
Egg:
0.23 mm; oval; pale
brownish yellow when laid, later becoming reddish
brown.
First-instar nymph:
0.3 mm long; oval-bodied
and rusty red in colour.
0.32
×
DESCRIPTION
Adult female (scale):
5-6 mm long; barnacle-like,
rectangular in outline and strongly convex; pinkish
white when young, but later becoming reddish.
First-
instar nymph:
purplish red and oval-bodied.
LIFE HISTORY
After mating, each female deposits many hundreds of
eggs over a period of several weeks, typically from May
onwards. These eggs remain under her body and hatch
3-4 weeks later. Nymphs pass through three instars
before attaining the adult stage, differences between the
sexes becoming apparent in the final instar. The scales
tend to occur along the major leaf veins or in clusters
along the shoots. The pest excretes considerable
quantities of honeydew and colonies are often attended
by ants. In particularly favourable (e.g. coastal) districts
LIFE HISTORY
Adult females occur on the branches and stems of host
plants, eggs (sometimes several thousand per female)
being deposited in the late spring. The first-instar
nymphs eventually invade the leaves, where they attach
themselves to the upper surface and begin feeding.
Later, as third-instar nymphs, individuals migrate back
to the branches and stems. Here, they become sedentary
and then overwinter, eventually attaining the adult
stage.
208
209
208
Female fig wax scale (
Ceroplastes rusci
) and second-
instar nymphs.
209
Citrus wax scale (
Ceroplastes sinensis
).
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