Establishment in Australia of Trichopoda giacomellii (Blanchard) (Diptera : Tachinidae), a biological control agent for Nezara viridula (L.) (Hemiptera : Pentatomidae)

Releases of Trichopoda giacomellii (Blanchard) for biological control of Ne zara viridula (L.) took place at sites in western New South Wales and south -eastern Queensland between 1996 and 1999. Trichopoda giacomellii became es tablished near Moree in north-western New South Wales, whereas establishmen t at sites near Brisbane has not been confirmed. Releases of adult T. giaco mellii and of parasitised N. viridula were made either directly onto host p lants (1996 and 1997) or following temporary confinement in a field cage (1 998 and 1999). Parasitism of N. viridula adults by T. giacomellii ranged fr om 9 to 72% between January 1999 and February 2000, and was 42% of adults d uring diapause. The methods employed to establish T. giacomellii in this st udy are compared with other attempts to establish Trichopoda spp. elsewhere in the world. Release methodologies that limit immediate dispersal of the agent and/or their progeny are recommended for establishing Trichopoda spp.