Biology Reference
In-Depth Information
Family
PSYLLIDAE
(psyllids or suckers)
Typhlocyba bifasciata
Boheman (
33
)
Hornbeam leafhopper
This common yellow and black leafhopper breeds on
elm (
Ulmus
) and hornbeam (
Carpinus betulus
).
Infestations occur throughout the summer and lead to
noticeable silvering of the leaves. The adults and
nymphs often occur in large numbers on the underside
of infested leaves, with the cast skins of earlier instars
or generations clearly visible. Adults are 3.2-3.7 mm
long, with pale yellow elytra, each marked with a pair of
black crossbands or with the basal two-thirds mainly or
entirely black. The characteristic pattern on the elytra
readily distinguishes this species from
Edwardsiana
flavescens
(p. 32) and from other leafhoppers associated
with elm or hornbeam.
Adults very active, with relatively large, membranous
wings and strong hind legs adapted for jumping. Wing
venation characteristic; a pterostigma present or absent.
Nymphs often flat and scale-like, and usually slow-
moving; they produce a white, waxy secretion and
masses of sticky honeydew. Most species are free-living
but some breed within leaf galls.
Acizzia uncatoides
(Ferris & Klyver)
Acacia sucker
An important Australian pest of silk tree (
Albizia
) and
wattle (
Acacia
). Now established in many other parts if
the world, including southern Europe (e.g. France, Italy,
Portugal and Spain) and the USA.
Typhlocyba quercus
(Fabricius) (
34
)
Although most often noted on oak (
Quercus
), causing
extensive discoloration of the leaves, this generally
common species is also associated with various other
hosts, including birch (
Betula
), hornbeam (
Carpinus
betulus
), smoke bush (
Cotinus coggygria
) and southern
beech (
Nothofagus
). Adults are 3.0-3.5 mm long, with
the elytra mainly white, marked with greenish yellow to
yellowish brown and with prominent brick-red to
orange patches. They occur from July to October.
DESCRIPTION
Adult:
fore wings hyaline, with grey or brownish
markings and pale yellow veins; body varying from pale
yellow to green, brownish orange or dark brown, with
grey markings.
Egg:
yellow to orange.
Nymph:
mainly
pale yellow to yellowish orange or greenish yellow,
with a darker head and dark markings on the thorax and
abdomen; eyes reddish; antennae short and dark tipped.
LIFE HISTORY
Eggs are laid on buds and the underside of leaves, and
hatch shortly afterwards. The flat-bodied nymphs then
pass through five instars before moulting into adults.
There are several (often up to eight) generations
annually, with adults and nymphs overwintering. In
addition to wax, the pest produces considerable
quantities of honeydew upon which sooty moulds
subsequently develop.
33
34
33
Hornbeam leafhopper (
Typhlocyba bifasciata
).
34
Adult of
Typhlocyba quercus
.
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