Choosing blight fungicides with good rainfastness should be a key consideration for potato growers this season, says Dow AgroSciences.

‘Weather proof’ products will be particularly important during showery conditions or where the crop is irrigated, said the firm’s principal biologist, Andy Leader.

“Farmers need blight fungicides that can make the most of any spray days available and allow them to keep to their planned spray intervals.”

According to Mr Leader, British Potato Council trials have shown that the best foliar and tuber blight control came from a programme consisting of two treatments of Epok (mefenoxam + fluazinam), followed by Electis (zoxium + mancozeb) from stable canopy onwards, and then altering with Ranman TP (cyazofamid + adjuvant) up until desiccation.

“When stable canopy is reached, blight sprays used from then on need to provide strong foliar blight protection, offer good tuber blight protection, have a strong anti-resistance position and be highly rainfast,” he added.

For more on the potential blight threat this season, see the Arable section of this Friday’s Farmers Weekly magazine (9 June 2006).