Results from the first year of a project aiming to look at the practical implications of differences in triazole fungicide resistance should be available by the end of the year, Hans Cools, a researcher from Rothamsted Research believes.
The DEFRA-funded LINK project is investigating, among other aims, whether using prochloraz in septoria control programmes can be used to help sensitise or change the resistance status of septoria populations.
Previous research had found that several different mutations in the septoria fungus caused triazole fungicides to lose sensitivity, and that some of these were specific to particular triazoles, he told the British Crop Production Council’s International Plant Protection Congress.
For example, tebuconazole is less effective when the septoria fungus carries the I381V mutation, and spraying with that fungicide selects for that particular mutation.
But prochloraz, in contrast, negatively selected for I381V, instead selecting for isolates carrying the V136A mutation, Dr Cools explained.
In theory, that could allow growers to spray different azole fungicides to try to select septoria populations that would be more easily controlled, but Dr Cools believed that it wouldn’t be quite as simple as that. “I’m confident of being able to select for various mutations, but not necessarily that you can sensitise crops to make weaker azoles work better.
“I’m certainly not recommending prochloraz / tebuconazole only control programmes. Growers will still need to be using the stronger triazoles for control.
“But the question arises if other azoles slip can we use this information to help them?” he concluded.
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