Galling guilds associated with Acacia dealbata and factors guiding selection of potential biological control agents.

Abstract

The Australian tree Acacia dealbata Link (Mimosaceae) invades natural ecosystems in both the Northern and Southern Hemispheres, including areas beyond its natural range in Australia. Biological control is under development in South Africa using the seed-feeding curculionid Melanterius maculatus Lea. A diverse range of galling insects occur on A. dealbata in Australia, most exhibiting high levels of host specificity and niche partitioning within their host. Galling insects have successfully contributed to biocontrol of other Acacia species in South Africa. Australian galling insects from A. dealbata have considerable potential for adoption as novel or complementary biocontrol agents. Factors governing the selection of potential agents are considered in the context of impact on the host, efficacy and compatibility with the utilization of the host for timber, pulp, floriculture and fire-wood harvesting, particularly in resource-poor regions of the world. The potential for biological control of A. dealbata in invaded habitats in Australia is also discussed.