Insects - Pests of Ornamental Trees, Shrubs and Flowers - page 394

Family EULOPHIDAE Family EURYTOMIDAE

A group of tiny insects, most of which are parasitoids. A varied group of tiny chalcid wasps, including

phytophagous species and parasitoids.

Leptocybe invasa Fisher & La Salle
Blue gum chalcid
A major new, invasive pest of Eucalyptus . First
discovered (as recently as the year 2000) in the Middle
East, but probably of Australian origin. Now present in
various parts of Africa, Asia, North America and southern
Europe, including France, Greece, Italy, Portugal and
Spain.

Eurytoma orchidearum (Westwood)
Cattleya 'fly'
A tropical Central and South American pest of orchids,
especially Cattleya . Accidentally introduced along with
host plants to many other parts of the world, including
Europe.

DESCRIPTION
Adult: 4-5 mm long; head and thorax dull black;
abdomen black and shiny. Larva: up to 5 mm long;
creamy white.

DESCRIPTION
Adult female: 1.2 mm long; body dark brown, with a
metallic blue or green sheen; legs and antennae pale.

LIFE HISTORY
This devastating species breeds parthenogenetically, the
females depositing eggs in the upper side of young
leaves, on either side of the midrib. Eggs are also laid in
leaf stalks and shoots. Affected tissue turns corky and
swells, and also changes colour from green to pink, and
eventually becomes light brown or red. Adult exit holes
also become evident in the walls of mature galls. There
are two or three overlapping generations annually.

LIFE HISTORY
Adult female wasps insert eggs singly in the rhizome of
host orchids, often depositing several in one and the
same plant. The eggs hatch 1-2 weeks later. Larvae
then feed on the internal tissue, each forming a large
cavity. Feeding galleries often coalesce, and larvae
then develop gregariously. Larvae are fully grown in
2-3 months. They then pupate internally, and adults
emerge shortly afterwards. There are several
generations annually.

DAMAGE
Galls cause stunting of growth and loss of vigour, and
the impact on young trees and seedlings is considerable.
Premature leaf fall, dieback of shoots and death of
severely damaged trees are also recorded.

DAMAGE
Infested rhizomes are deformed and weakened. As a
result, vegetative growth is interrupted, and attacked
plants usually fail to flower. Damaged rhizomes are also
liable to be invaded by bacterial and fungal pathogens.

Ophelimus maskelli (Ashmead)
Eucalyptus gall wasp
In recent years this Australian pest has become well
established in the Mediterranean Basin (including
France, Greece, Italy and Spain) on Eucalyptus , upon
which it forms tiny ( c . 1 mm diameter) pimple-like galls
on the upper surface of young expanded leaves. The
pest has also spread to Portugal, and it or a close relative
is believed to have been accidentally introduced to
England. Although leaves may be peppered with galls,
and infestations may result in premature leaf fall, the
pest is not considered as devastating as Leptocybe
invasa (see above). There are up to three generations
annually.