Evil weevil biocontrol
Your enemy’s enemy is your friend – at least when it comes to biocontrol of pests. Weevils that have slashed timber growth by up to 30 per cent in some Western Australian eucalypt plantations will be the subject of a new and globally-significant research project co-funded by FWPA. The eucalypt weevil Gonipterus scutellatus was once thought to be a single species, but is now known to consist of at least 10 closely-related species – which may explain why previous efforts at biocontrol have been hit and miss.
Australian researchers will delve deeper into parasitic insects used – with varying degrees of success – for biocontrol against Gonipterus weevils.
With global funding, the researchers from the University of the Sunshine Coast will identify which parasitoids are most effective against particular Gonipterus weevil species and which work best in different climates. (Parasitoids are parasitic species that kill their hosts.)
They will also create a model bio-control development template that can be used for future development of bio-control agents of pests that affect economically important plant species, such as leaf beetles.
Currently, Anaphes nitens, a species that parasitises weevil eggs, is used as a bio-control agent with varying degrees of success.
Lead researcher Dr Simon Lawson said that the problem could be related to poor climate matching of the parasitoid, or to a mismatch between the particular species of weevil and the parasitoid.
“The end game is that we want to improve biological control of these pests worldwide, and make eucalyptus plantations more productive as a result,” he said.
“If we can get this right, we can also improve our environmental credentials and save industry money by reducing the need for pesticides.”
A. nitens occurs naturally on Australia’s eastern coast, where the weevils are under effective biocontrol in most regions. However, the weevil has been implicated as one of the factors for a large-scale dieback in the Monaro region of NSW, while significant outbreaks in Western Australia have caused crown defoliation levels of over 40 per cent and cut timber growth rates by 20-30 per cent.
The project is a fantastic example of collaborative research, development and extension. It has received funding and research support from universities and plantation industry groups nationally and internationally. Project partners include; Forest & Wood Products Australia, the Forestry Science and Research, Institute of Brazil and Forestry South Africa, the University of the Sunshine Coast, Murdoch University and the Integrated Plantation Management Group (Australian Bluegum Plantations, PFOlsen, WA Plantation Resources and Bunbury Fibre Plantations).