Biological Control of Insect Pests: Southeast Asian Prospects - EcoPort

BRAZIL
4.12 Nezara viridula 221
parasitisation by Trichopoda giacomellii. Adverse climatic conditions
(heavy rain) played a minor role in nymphal mortality (Liljesthršm and
Bernstein 1990). Parasitisation of N. viridula eggs by T. basalis rose to a
maximum of 90% in autumn although 33% of the parasitoids died, the
majority (60%) in the pupal stage (Liljestršm and Camean 1992).
In Rio Grande do Sul the main causes of mortality of N. viridula eggs laid
throughout the season on soybean were infertility (2.7%: relatively
constant), failure to hatch (14.1%: fluctuating), parasitisation (24%:
relatively constant) and predation (17.3%: relatively constant) (Moreira and
Becker 1986a). Three scelionid parasitoids were present, T. basalis,
Trissolcus sp. and Telenomus mormideae. T. basalis killed a greater number
of eggs and attacked a larger number of egg rafts than the other species
(Moreira and Becker 1986b). A complex of polyphagous predators did not
discriminate between parasitised and unparasitised eggs and were
responsible for 25.5% mortality. The predators were responsible for 17.3%
mortality of N. viridula and 34% of T. basalis (Moreira and Becker 1986c).
Predation on host eggs was the main cause of mortality of T. basalis in the
pre-emergence period (Moreira and Becker 1987).
The tachinid fly Trichopoda giacomellii (= Eutrichopodopsis nitens) is
the most important parasitoid of N. viridula in northern Paran‡ State. The
level of parasitoid attack varies according to the plant on which the host is
feeding and is highest when soybean is not available (Panizzi 1989).
Although T. basalis (introduced) and Telenomus mormideae (native) were
already present on the Cerrados area, Kobayashi and Cosenza (1987)
introduced from Japan 5 additional species. In order of decreasing efficacy
in parasitisation and adult emergence these were Trissolcus mitsukurii,
Ooencyrtus nezarae, Telenomus chloropus, Telenomus gifuensis and
Trissolcus sp.. Of the introduced species, T. mitsukurii parasitised eggs of all
major pentatomid species throughout the year and also survived the dry
winter season. In addition, it was the dominant competitor on egg masses.
However, Bennett (1990) reports, more recently that it is not definite that
permanent establishment has been achieved. When compared with
T. basalis, the latter parasitised about 90% of exposed eggs with 60% adult
emergence, whereas T. mitsukurii achieved about 70% parasitisation and
40% emergence (Kobayashi and Cosenza (1987). In northern Brazil,
Ferreira (1986) reported 40% parasitisation of N. viridula eggs by T. basalis
and that Telenomus mormideae was also abundant.
In the Federal District of Brazil the egg parasitoids Trissolcus mitsukurii
and Gryon japonicum, introduced from Japan, gave good levels of
parasitisation (Kishino and Teixeira 1994). In Parana State T. basalis,