A product sold by health food shops to treat high cholesterol or for brushing teeth has been used to rescue ailing trees at the Blackall Saleyards.
Diatomaceous earth, a naturally occurring sand made from the microscopic skeletons of algae fossilised over millions of years, also has many industrial uses and was what expert nurseryman Neil Fisher turned to in an effort to kill the Indian wood weevils attacking the hundred or so trees that are a feature of the yards in western Queensland.
The unusual treatment was deployed because the yards are one of only two in Australia that have organic status, meaning that the borers couldn't be sprayed with chemicals.
Mr Fisher said the insects had first been able to mount their attack a few years ago when a storm stripped branches from a number of trees.
"Open wood is very susceptible to borers," he said. "They were weakening but saveable."
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It was back to the books for the experienced gardener, to research techniques used before chemicals became commonplace in gardens.
The first pesticide products containing silicon dioxide or diatomaceous earth were registered in 1960 to kill insects and mites.
Blackall chemist Ian Kinsey, who also owns a health food store in Rockhampton, was able to source a bulk supply of the silicon dust.
"I'm based in Rockhampton so I was able to trial how to use it there first," Mr Fisher explained.
After cleaning all the trees, tomato sauce bottles were used to puff the super-fine dust into the tree's holes, where it has to come into contact with the insects to cut into them and dry them out.
Any wounds were then sealed using sculptor's clay, and water-based house paint was put over the top of that.
Mr Fisher said the exercise had had lots of benefits, both in supporting a local business and in upskilling the regional council garden staff.
"They are the custodians of the way the town looks so I was very happy to pass on knowledge," he said.
"As well as that, the tree canopy is so important to the yards at Blackall - they are what make them one of the best saleyards in the country."
Mr Fisher said the general stress experienced from years of drought would have contributed to the trees' troubles.
Ironically, one of the large fig trees planted in the 1980s blew over in a wind storm in January but Mr Fisher said it hadn't been affected by borers.
"It was close to the sale ring and washdown points, which all drained to that root ball," he commented.
Sally Gall
Based at Blackall, CW Qld, where I've raised a family, run Merino sheep and beef cattle, and helped develop a region - its history, tourism, education and communications. Get in touch at 0427 575 955 if you've got a story idea for me.
Based at Blackall, CW Qld, where I've raised a family, run Merino sheep and beef cattle, and helped develop a region - its history, tourism, education and communications. Get in touch at 0427 575 955 if you've got a story idea for me.
