Insects - Pests of Ornamental Trees, Shrubs and Flowers - page 123

251 252

251 Larva of a longhorn beetle (family Cerambycidae). 252 Male and female musk beetles ( Aromia moschata ).

infestation, and this is a clear indication of the presence
of larvae. Development is completed in three or
more months. Fully fed larvae then pupate in chambers
at the end of their feeding galleries. Adults emerge at
any time from spring to autumn, and there may be up to
three generations annually.

galligenous tissue, the affected area swelling
considerably. Eggs hatch in about two weeks. Larvae
then bore into the expanding galligenous plant tissue,
and gradually extend their feeding galleries upwards
into the pith. The local swellings on host trees are
clearly visible in the first summer, and become
particularly so in the following year. Pupation takes
place close to the surface during the spring of the third
year, and adults emerge a few weeks later. Larval
survival is dependent upon the continued production of
galligenous tissue by the host tree, and in wet summers
and in damp sites (when a plant's reaction to attack
is less marked) many larvae fail to complete their
development.

DAMAGE
Larvae tunnel within the trunks and branches of infested
trees, often causing the foliage to wilt. Liquid
commonly seeps from holes or cracks in the bark, and
infested branches if not whole trees may be killed.
Although attacks most often occur on trees already
under stress, healthy trees are also at risk.

Saperda populnea (Linnaeus)
Small poplar longhorn beetle
larva

DAMAGE
Infested stems are gnarled, and are eventually snapped
off by the wind. Attacks on nursery stock and recent
transplants often result in deformation and death of host
plants.

small poplar borer
An important pest of Populus , especially aspen
( P. tremula ) and hybrid black poplar ( P. serotina ).
Infestations are most important on young established
trees and transplants, and in nurseries. Widespread and
generally common in Europe.

=

DESCRIPTION
Adult: 9-15 mm long; mainly black, patterned with
yellow on head, thorax and elytra; antennae black and of
moderate length, most segments with grey hairs basally.

LIFE HISTORY
Adults occur from mid- or late May to July, and feed on
the leaves and green shoots of host plants. Eggs are laid
singly, each at the base of a deep, horseshoe-shaped
incision bitten into the bark of a small stem or branch.
Several incisions may be made close together on the
same stretch of wood. The plant reacts by producing