Biological Control of Insect Pests: Southeast Asian Prospects - EcoPort

4.12 Nezara viridula 233
Ectophasiopsis arctuata
This tachinid is common on N. viridula adults in Chile. Following its
introduction to Easter Is it brought this bug under successful biological
control (Ripa and Rojas 1989).
Gymnosoma rotundata
This tachinid parasitises N. viridula in Japan where up to 5% parasitisation is
recorded (Kiritani et al. 1963). It is widespread in Palaearctic regions and
attacks many hosts, including Nezara antennata, in Japan and Korea.
Gymnosoma clavata has been recorded once from N. viridula in Europe
(Herting 1960).
One other tachinid has been reported once from N. viridula,
Cylindromyia rufifemur from Australia (Cantrell 1984).
Comments
Although predators are undoubtedly important natural enemies of
N. viridula, particularly of its early stages, most are generalists which are
unlikely to be approved nowadays by quarantine authorities for introduction
as biological control agents. This situation is likely to be partly offset by the
fact that most countries possess a suite of generalist predators, some of
which are likely to attack N. viridula.
The species of egg parasitoid most closely associated with N. viridula
are concentrated in Africa and Japan. Elsewhere its eggs are parasitised by
introduced species or by native species that have expanded their activities
from native bugs. Indeed, it seems likely that the complex of Japanese
parasitoids has probably expanded its host range from the oriental stink bug
N. antennata of Japanese origin, just as the complex of Central and South
American tachinids has clearly expanded to N. viridula adults from adults of
native bugs.
Successful biological control of N. viridula has been achieved in many
countries to which it has spread this century. These include a vast area (but
not all) of Australia, also New Zealand, Hawaii and several other Pacific
islands. The prospects are good for reducing its pest status in many other
areas where effective parasitoids are not yet present. This might involve the
introduction of additional species or strains of Trissolcus. In addition several
of the many other parasitoids known to attack eggs (species in the genera
Telenomus and Gryon) are well worth considering. In the Ethiopian region a
tachinid (Bogosia antinorii) is an important parasitoid of adults and large
nymphs and in the Americas there are at least 4 tachinid species worthy of
consideration: Trichopoda pennipes: USA; T. pilipes: West Indies;