RESEARCHERS studying biological controls to manage fireweed visited Bega on Monday.
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Postdoctoral research fellow of the University of KwaZulu-Natal Kerinne Harvey and research scientist with the CSIRO Andy Sheppard gave a presentation to members of the Bega Valley Fireweed Association about the progress of a study the group has been lobbying for.
The study has been looking at fireweed in its native South Africa, examining the biological controls of insects and pathogens that specifically affect fireweed (senecio madagascariensis) to hopefully apply in Australia.
Dr Sheppard said while there are promising results, a big challenge is as there are many closely related native plants to fireweed in Australia, more research needs to be done to find a biological control that only impacts on the invasive species.
One possible control he said he was very excited about is the flea beetle; a species of which that came from Spain has been very successful in controlling Paterson’s curse.
Dr Sheppard said a species of flea beetle has possibly been identified that would not get rid of fireweed completely, but would help suppress it so it no longer causes problems in paddocks.
Dr Harvey discussed the preliminary results of the study, which suggest when insecticide is sprayed on fireweed instead of fungicide, the growth rate is better, which means insects have a bigger chance of impacting on the plant – although Dr Harvey did stress more research needs to be done.
Dr Harvey also talked about a study by an associate that examined how temperature influences fireweed.
The findings in this study suggest the germination of fireweed in southern Australian regions takes longer than in the north, but the plants grow bigger, while in the north there is a reduction in survival and the plants are more likely to be mutated.
She said this suggested the invasion of fireweed in southern Australia will continue while it will be limited in the north.
Bega Valley Fireweed Association (BVFA) member Noel Watson said the results discussed by the researchers were “encouraging”, as the fireweed situation in the Bega Valley was bad.
“This year the Valley has virtually gone yellow twice,” he said.
Bega Valley Shire Councillor Tony Allen agreed the problem was grim.
“It’s getting worse, I think the word is ‘debilitating’,” he said.
“You feel useless and embarrassed that you can’t deal with this issue on your farm – with this it’s just totally out of control.”
Dr Sheppard said no biological controls would be ready to be released for another five to six years.
“I don’t care how long it takes as long as they get it, because we need it in Australia,” Mr Watson said.
WHEN the fireweed researchers said a possible biological control agent was the flea beetle, the crowd became very interested about the insect and asked many questions regarding it.
Flea beetle grubs feed on the roots and the adults emerge in late spring to feed on the plant, and greater numbers of the beetle mean fireweed would have less chance of surviving such hardships as drought.
While the flea beetles are quite specific in the plants they live off, the problem is finding one strain of the beetle that just eats fireweed.
Research scientist with the CSIRO Andy Sheppard said the flea beetles probably evolved with the plants, as fireweed diversified and evolved the beetles did with it.
Animals that have evolved to be specific generally can’t diversify so it would not be likely for the beetle to move onto an Australian native.
“We don’t know very much about it, but it is the right kind of biological control agent we are looking for,” he said.