Biology Reference
In-Depth Information
Family
RHYNCHITIDAE
Family
ATTELABIDAE
(leaf-rolling
weevils)
A small group of weevils whose antennae lack a long
scape, each segment being of similar length; mandibles
dentate.
A group of weevils whose antennae lack a long scape,
each segment being of similar length; prothorax much
narrower than the abdomen.
Neocoenorrhinus aequatus
(Linnaeus) (
304
)
syn.
Rhynchites aequatus
(Linnaeus)
Apple fruit rhynchites
A small (2.5-4.5 mm long), reddish-brown to purplish-
bronze weevil, associated primarily with hawthorn
(
Crataegus
) but also attacking certain other rosaceous
ornamental trees and shrubs, including crab-apple
(
Malus
), flowering cherry (
Prunus
) and
Sorbus
. The
adults feed in the spring on the buds, flowers and
foliage, causing slight damage. The females later attack
the berries, depositing eggs in small pits bitten into the
flesh. Larvae feed in the developing fruits for about
three weeks, eventually dropping to the ground to
pupate in the soil in earthen cells. There is just one
generation annually. Infestations on ornamentals are not
important.
Apoderus coryli
(Linnaeus) (
305-308
)
Hazel leaf roller weevil
A generally common but minor pest of common hazel
(
Corylus avellana
); at least in mainland Europe, attacks
also occur on alder (
Alnus
), beech (
Fagus sylvatica
),
birch (
Betula
), European hop-hornbeam (
Ostrya
carpinifolia
) and hornbeam (
Carpinus betulus
). Present
throughout Europe.
DESCRIPTION
Adult:
6-8 mm long; mainly red, with a black,
elongate, pear-shaped head, black legs and antennae.
Egg:
1.0-1.5 mm long; oval, orange.
Larva:
up to
10 mm long; bright orange, with a brown head.
Pupa:
6-8 mm long; orange.
LIFE HISTORY
Adults emerge in the spring to feed on the leaves of
hazel. Eggs are laid in May and June, singly or in small
groups, usually in the midrib towards the tip of an
expanded leaf. The leaf blade is then severed near the
base, the cut extending from one edge to or just beyond
the midrib (cf.
Attelabus nitens
, pp. 149-50); the cut
tissue then curls laterally to remain suspended from the
unsevered part of the leaf blade as a stumpy, cigar-like
leaf roll. The larvae develop within these leaf rolls
and then pupate, new adults appearing at the end of July
or in early August. Larvae of a second generation
complete their development in the autumn; they
eventually overwinter on the ground, within their fallen
habitations, and pupate in the spring.
304
DAMAGE
Although infestations are sometime established on
ornamental plants and larval habitations might be very
numerous, damage caused is unimportant.
Attelabus nitens
(Scopoli) (
309-310
)
syn.
A. curculionoides
Linnaeus
Oak leaf roller weevil
A locally common but minor pest of oak (
Quercus
);
also found on alder (
Alnus
), common hazel (
Corylus
avellana
) and sweet chestnut (
Castanea sativa
).
Widespread in mainland Europe, northwards to
southern Scandinavia; in the British Isles most
numerous in the southern half of England.
304
Apple fruit rhynchites (
Neocoenorrhinus aequatus
).
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