Fighting Fungus With Fungus
Kiwifruit growers are learning how a fungus-based compost can help them to destroy another fungus that threatens their livelihood.
The trichoderma compost "inoculant" results from a project undertaken by Gro-Chem NZ Ltd, a Porirua agricultural specialties and research and development firm, with investment from Technology New Zealand.
"Something was needed to put the trichoderma fungus into a cheaper and more easily used form so it could effectively kill armillaria, which attacks the roots of kiwifruit trees," Gro-Chem marketing director Philip Hutchinson says.
Armillaria was first spotted overseas last century.
It was found in New Zealand kiwifruit in 1955.
It attacks the roots of plants, and usually does considerable damage before it is discovered.
It eats the wood from within, coming up underneath the bark.
Surveys of Bay of Plenty growers in 1997 found armillaria in 60 percent of orchards.
Forty-three percent of growers reported that conventional spraying treatment had failed control the fungus.
That left growers with the choice of either pulling out their trees and replacing them, or digging up the ground, sieving and shaking the soil, replacing and then fumigating it.
Trichoderma, which originated in England, has been around for some time.
Research has shown it to be a useful fungus-killer.
"Our project was to see how we could commercialise it, to bring the price down.
Growers needed something they could apply for $5-$6 a tree, instead of $30, which was just too expensive for them," Mr Hutchinson says.
Trichoderma is sold as a coarse powder and has received a Bio-Gro certificate of approval from the Biological Producers and Consumers Council for an organic product.
Trichoderma can be applied in a paste brushed on to kiwfruit plants or as a dip for the roots.