Insects - Pests of Ornamental Trees, Shrubs and Flowers - page 120

Family BUPRESTIDAE

DESCRIPTION
Adult: 7-11 mm long; coppery red to purplish red;
hind margin of pronotum strongly sinuate. Larva:
up to 22 mm long; body dirty creamy white and
dorsoventrally flattened, with the thoracic region
noticeably enlarged; tip of abdomen with a pair of
pointed, forceps-like projections.

A family of mainly tropical beetles, with relatively few
European representatives. Adults (1-12 mm long) are
more or less elongate, and usually distinctly metallic in
appearance.
Larvae (sometimes known as 'flat-headed borers')
are dorsoventrally flattened, often with a very large
prothoracic segment into which much of the head is
retracted. The larvae are mainly wood-borers, and feed
in galleries excavated beneath the bark or rind of host
plants.

LIFE HISTORY
Adults usually emerge in early June, but their
appearance may be delayed by cool, wet weather. At
first they browse on the foliage of host trees, before
eventually mating. Larvae feed beneath the bark of trees
from July onwards, each forming a long, zigzag-shaped
gallery in a small branch; galleries up to 1 m in length
are reported on some hosts. The larvae usually pupate in
the following May. However, unfavourable conditions
significantly delay their development, and individuals
may then necessarily pass through two winters.

Agrilus aurichalceus Redtenbacher
Raspberry jewel beetle
larva rose stem girdler

A pest of rose ( Rosa ) in mainland Europe from France
eastwards. An introduced species in the USA.

=

DESCRIPTION
Adult: 4.5-7.0 mm long; mainly metallic olive-green to
metallic greenish-blue; elytra elongate, with a sinuous
outline, and distinctly swollen between the middle
and apex.

DAMAGE
Infestations are particularly damaging on young hosts,
rendering trees liable to attack by secondary organisms
such as bark beetles. Old, vacated galleries become
particularly noticeable several years after their
formation, each developing into a large and distinctive
scar on the bark as the host tree continues to grow.
Adults feeding on foliage remove irregular sections
from the edges. Such damage is of no significance,
although on young leaves the incised areas subsequently
become necrotic.

LIFE HISTORY
Larvae feed singly within the stems of host plants, each
burrowing upwards just beneath the epidermis from the
point at which the egg was deposited. At first, a
relatively tight spiral gallery is formed, which causes a
localized swelling (pseudo-gall) about a centimetre
long; later, the spiralling becomes more 'open' and the
gallery straightens before terminating in an elongated,
flask-shaped pupal chamber a few centimetres above
the level of the pseudo-gall. Typically, the larval gallery
remains filled with frass, as there are no external
openings through which this might be expelled.
Pupation occurs in the spring. Adults are active from
May to July.

248

DAMAGE
Larva-infested plants are progressively weakened. Also,
adults browse on the leaves and cause noticeable loss of
tissue.

Agrilus sinuatus (Olivier) ( 248 )
Pear jewel beetle
Associated mainly with pear and other rosaceous fruit
trees, but also attacking ornamental crab-apple ( Malus ),
hawthorn ( Crataegus ) and Sorbus . Widely distributed in
central Europe and currently extending its range
northwards. Also present in North Africa and an
introduced pest in the USA. 248 Pear jewel beetle ( Agrilus sinuatus ).