In the sponsors’ area of FAR’s Crops 2020 event companies were promoting their latest products which, in Corteva’s case, was novel cereal fungicide Questar.

“It’s a completely new mode of action,” R&D manager Bernard Harris told visitors.

Harris said it had market-leading activity against septoria and was best used as a protectant, partnered with a stacked DMI (triazole) such as Kestrel. A mix was best used in sequence with an SDHI mix at a later or earlier timing.

The active ingredient, fenpicoxamid, was a natural product made by fermentation of soil-borne Streptomyces bacteria and was the first of a new class of fungicides called picolinamides. As such it had a key role to play in resistance management, providing an alternative to SDHI fungicides.

“Resistance to SDHI’s has developed quickly overseas,” he said.

Corteva says there’s a moderate to high risk of cereal diseases becoming resistant to picolinamides hence why Questar should be tank-mixed with another fungicide with an alternative mode of action.

The Questar label stresses tank mixes must be used immediately with constant agitation. Harris said Questar is compatible with most plant growth regulators and broad-leaved herbicides.