Insects - Pests of Ornamental Trees, Shrubs and Flowers - page 97

plants are also reported in northern Europe but here the
insect is able to survive only under artificial conditions.

LIFE HISTORY
Under suitable conditions, breeding is continuous and
infestations build up rapidly, particularly on the
underside of the leaves of both young and established
monocotyledonous pot plants. Tests of the different
sexes are often clustered separately, and dense
groupings impart a distinctive waxen appearance to
infested parts of plants.

Lepidosaphes machili (Maskell)
Cymbidium scale
In northern Europe, infestations of this scale insect are
sometimes noted on the leaves and stems of
greenhouse-grown Cymbidium . The tests are about 2
mm long, and mussel-shaped but rather narrow.
Although disfiguring host plants, they are rarely
numerous and are of only minor importance.

DAMAGE
Infestations disfigure and weaken host plants; the thick
masses of white wax associated with male tests are most
unsightly.

Lepidosaphes ulmi (Linnaeus) ( 205 )
syn. Mytilaspis pomorum (Bouché)
Mussel scale
Generally abundant throughout most of Europe on
various trees and shrubs, including fruit trees and
ornamentals such as Ceanothus , common box ( Buxus
sempervirens ), Cotoneaster , crab-apple ( Malus ),
hawthorn ( Crataegus ), heather ( Erica ), Japanese quince
( Chaenomeles japonica ) and rose ( Rosa ). The female
tests are 2.0-3.5 mm long, elongate mussel-shaped and
grey to yellowish brown. They often encrust the bark of
mature host plants but cause little or no damage. Eggs
overwinter, protected by the female tests, and hatch in
late May or June. First-instar nymphs then wander over
the branches and trunks before settling down to feed.
They reach maturity by the end of July, and eggs are laid
in late August and September.

Lepidosaphes beckii (Newman) ( 202 )
Citrus mussel scale
In southern Europe, a pest of Citrus, Croton, Elaeagnus,
Hibiscus and many other plants; also widely distributed
in tropical and subtropical parts of Africa, America and
Asia.

DESCRIPTION
Female test: 2-4 mm long; elongate and broadly
mussel-shaped; purplish brown. Male test: 1 mm long;
similar to female test, but more elongate. Egg: minute,
oval and white. First-instar nymph: 1.3 mm long;
elongate-oval and flattened; brownish white.

LIFE HISTORY
After mating, each female deposits a batch of 50-100
eggs beneath the shelter of the test and then dies.
Following egg hatch, the first-instar nymphs move onto
the leaves, shoots and other parts of host plants, where
they soon settle down to feed and mature. The lifecycle
from egg to adult is completed in 2-4 months, and there
are several generations annually.

DAMAGE
Heavy infestations cause premature leaf fall and death
of young shoots. The pest often occurs amongst
colonies of California red scale ( Aonidiella aurantii )
(p. 101).

205

Lepidosaphes conchyformis (Gmelin in
Linnaeus) ( 203-204 )
syn. L. ficus (Signoret)
Fig mussel scale
This species occurs outdoors in southern Europe. The
tests often cover the underside of the leaves of common
fig ( Ficus carica ) and cause a noticeable pale mottling
of the foliage, clearly visible from above. The tests are
about 2 mm long, relatively narrow, straight or slightly
curved and slightly expanded posteriorly. Infested 205 Mussel scale ( Lepidosaphes ulmi ).