The ACCase inhibitor clethodim could provide growers with a useful addition to the available chemistry used to kill blackgrass in broad-leaved crops, subject to approval.

The active is registered for use in many countries across the world and Interfarm UK is looking to bring the product to the UK market.

“You may question whether there is room for another ACCase inhibitor here when we have both enhanced metabolism (EMR) and target site resistance (TSR) to this group of chemistry,” said Stephen Moss of Rothamsted Research.

“However, we have shown in controlled experiments that clethodim is only affected by two of the 11 known TSR mutations and is not affected by EMR.”

The active ingredient was proved to be more effective than cycloxydim and propaquizafop where ACCase TSR was present in blackgrass populations.

Tepraloxydim, the current commercial standard within the “fop” and “dim” group, was also outperformed where clethodim was applied in oilseed rape in the autumn at 120g ai/ha.

“There is an opportunity for UK growers to improve their annual grassweed control in broad-leaved crops, but resistance management will be an issue,” said David Stormonth of Interfarm UK.

“If we want to prolong the life of this group then we need to look at sequences and mixing with different modes of action and also maximising the use of non-chemical controls,” he said.

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