Insects - Pests of Ornamental Trees, Shrubs and Flowers - page 143

Family APIONIDAE

LIFE HISTORY
Adults appear in the spring and then feed on the foliage
of various host plants. Egg laying begins from early
May onwards, when mated females initiate
characteristic larval habitations. Firstly, one or two eggs
are deposited in the upper surface of an expanded leaf;
the selected leaf is then severed neatly across on both
sides of the midrib, just beyond the base, the tissue
rolling into an elongate, cone-like tube. The suspended
material soon dries out. Cones formed on beech turn
rusty brown and are particularly obvious. Larvae are
fully grown in about three months. They then enter the
soil where they pupate. Adults emerge in the following
spring. There is a single generation annually.

A group of small, often narrow-bodied, dull-looking
weevils; antennae usually not geniculate, although basal
segment (scape) may be noticeably elongated.

Rhopalapion longirostre (Olivier)
syn. Apion longirostre Olivier
Hollyhock weevil
A destructive pest of hollyhock ( Alcea rosea ).
Originally found mainly in south-eastern Europe and
Asia Minor, but currently greatly extending its range in
Europe. First found breeding in England in 2006. Now
widespread and of some significance in the USA, where
it was first recorded in 1914.

DAMAGE
Infestations disfigure host plants and are often
extensive, with all leaves on certain shoots affected, but
damage is not of economic importance.

DESCRIPTION
Adult: 4-5 mm long; mainly black, with a grey
pubescence; legs yellowish or reddish yellow; rostrum
very long.

Deporaus tristis (Fabricius) ( 313 )
Maple leaf roller weevil
This relatively small (3.5-4.0 mm long), bluish-black
species is associated mainly with sycamore ( Acer
pseudoplatanus ); occasionally, beech ( Fagus sylvatica )
and oak ( Quercus ) are also hosts. The adults feed on the
leaves, removing significant amounts of tissue; they
also form characteristic, tightly wound leaf rolls within
which larval development takes place. Affected leaves
are sometimes found on amenity trees in mountainous
parts of Europe, from southern Germany southwards,
but infestations are not of significance. The weevil is
widely distributed in southern Europe.

LIFE HISTORY
Eggs are laid in early summer in the unopened buds of
hollyhock. Larvae then feed on the developing seeds for
4-6 weeks. Fully fed larvae pupate in situ , and new
adults emerge from the buds shortly afterwards. These
adults overwinter, there being just one generation
annually.

DAMAGE
Adults feed on buds and leaves, boring holes in the
tissue and causing extensive damage.

313

313 Larval habitation of maple leaf roller weevil ( Deporaus
tristis ) on Acer .