A LEADING researcher has said government policy in Denmark was accelerating fungicide resistance as the country had fewer options and higher costs due to taxes on more harmful active ingredients in fungicides.
Senior scientist Lise Jorgensen, from the Department of Agroecology at Aarhus University, was one of the keynote speakers at the Grains Research and Development Corporation (GRDC) research updates in Perth on February 27-28.
The areas of her research include disease management, disease forecasting, fungicide efficacy and resistance in cereals and other crops and concentrating on the optimisation and minimisation of fungicide use in cereals and fungicide resistance.
"WA grain growers are seeing the first signs of fungicide resistance to chemicals used to control plant diseases," Ms Jorgensen said.
"Like herbicide resistance, this can lead to rapid escalations in the cost of managing disease in grain crops."
Australia has had seven cases of fungicide disease resistance, which accounts for 14 per cent of total worldwide resistance.
Ms Jorgensen said European Union subsidies to farmers had driven up the cost of land, so while farmers had fertile soils and sufficient water - allowing them to produce similar total grains productions to WA's wheat production - farm sizes were very small with high costs of debt.
On top of this, Danish farmers were experiencing the same low grain prices that WA growers faced and there were considerable constraints on which products they were allowed to use in their crops, particularly pesticides.
"There are a lot of restrictions on pesticides and very strict procedures for the approval of pesticides; our focus is on groundwater and we cannot use any product which could pollute our groundwater," she said.
For example, while farmers in the United Kingdom, France and Germany had access to 12 different fungicides to treat septoria in wheat, Denmark could only use six.
Farmers generally spray fungicides one to three times with wheat and zero to two times to treat fungal disease in barley.
"Under the EU sustainable use directive, growers are to avoid using sprays, increase monitoring of crops and use alternatives to pesticides and use products that are considered least harmful - our tax system has been built on that."
Ms Jorgensen said products were ranked based on their toxicity, with the least harmful products taxed at a lower rate to more toxic - and more effective - fungicides.
"What happens is that while you can use different strategies and different products the cost can be high and up to half is a tax," she said.
"If you have a green, friendlier choice of chemical it is less tax and less cost, it might also be less effective in a resistance strategy - that is a drawback on the tax systems."
The speed in which fungicide resistance spread across Europe was further affecting which fungicides farmers could access, she said.
In some cases farmers had access to fungicides for only a few years before they were rendered ineffective.
"In 2003, in one season we went from very low levels of resistance to strobilurin in the start of the season to very high after just one treatment in the field," she said.
"By 2014 we could no longer use these products."
She said for Australian growers, in order to slow the incidence of fungicide resistance, it was important to grow resistant cultivars that needed less spraying, spray only when needed, alternate or mix between modes of action and constantly monitor to check the fungicide's efficacy.
