Many potato crops are now emerging alongside intense weed competition - with the continued dry weather conditions significantly reducing the efficacy of all residual herbicide treatments.
Syngenta potato manager Tom Whitworth is therefore advising growers to use the higher available rates of Retro, at up to 4.0 l/ha, to help them remove the larger and more aggressive weeds.
He said: "The higher rate of Retro will give faster and more robust kill of larger weeds. Cooler temperatures this week will give ideal conditions for Retro application and leave a clean seedbed for rapid crop growth."
He also reminded growers that Retro is the only diquat herbicide approved for use at up to 4.0 l/ha; other diquat products may only be used at a 50% lower 2.0 l/ha label approved rate.
Retro can be used on maincrop potatoes with up to 40% emergence, or 10% emergence of early varieties.
He said: "The higher rate will also be crucial for later planted crops where growers have waited until as close to emergence as possible before applying their Defy residual herbicide, when there may already be significant weed populations established."
Trials have shown Defy + Retro tank mix can be safely used up to 10% crop emergence, ensuring the crop can get away in a clean weed free seedbed with the longest possible residual activity.