A NEW method of controlling the potato disease of powdery scab could be a win for farmers, but the method is still at least five years away from formal recommendation.
Research undertaken by the Tasmanian Institute of Agriculture (TIA) is trying to develop new ways to control the powdery scab pathogen and get a better understanding of why it survives in the soil, how it wakes up and how it affects the potato.
TIA researcher associate professor, Calum Wilson, said it is hoped that this new control method - which is still only in its early days of research - could be a future tool for potato growers to minimise powdery scab.
He spoke about the widespread disease, which he labelled as a potato farmer's biggest headache, at the recent open day at the TIA's Forthside Open Day.
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"The pathogen sits asleep in the soil and lies dormant until you grow a potato crop," he said.
"The roots of a potato release certain chemical compounds, and this signal wakes up the pathogen which then follows the chemical scent in the soil, attacks the roots of the potato plant, making the potato diseased.
"You end up with scabs over the tubers. From a fresh market perspective it reduces the value, but it also disrupts root function and causes yield loss."
He said the new control method aims to trick the pathogen by releasing similar chemical compounds into the soil when there are no actual potatoes being grown.
When the pathogen finds a potato's chemical compounds its own germination method is stimulated.
We don't need to eliminate all of the pathogen but we know if we start to decrease the pathogen in the soil to a low level then the chance of disease is much lower and the impact of the disease on potato crops is much less.
- Associate professor Calum Wilson, Tasmanian Institute of Agriculture
This germination still occurs when the pathogen is tricked by the pseudo compounds but it dies after one day without affecting any potato plants, thereby reducing its power in the soil over the long term.
"The main [germination] spore that is released when the potatoes are present only lasts a day and then it dies," he said.
"By using this stimulation treatment and by tricking germination we can reduce the amount of pathogen in the soil.
"We don't need to eliminate all of the pathogen but we know if we start to decrease the pathogen in the soil to a low level then the chance of disease is much lower and the impact of the disease on potato crops is much less."
Associate professor Wilson said the stimulation method had been tested in pots and small plots, and is now reaching field trial stage.
"We are trying to get a program to push this research forward," he said.
"What we really need is to look at its efficacy within commercial production systems, look at the appropriate dosage rates, and the best methods of incorporation."
