High levels of rust have been reported in thick winter bean crops in East Anglia and, with the disease developing fast, growers need to act quickly, BASF has advised.

The disease – characterised by orange-brown pustules and small chlorotic spots on leaves and stems – is not normally seen until the end of June when it is controlled with the second spray, said the firm’s John Young.

But, this year, it needs “serious consideration now”, he said. “Severe rust infections during flowering and pod fill can cause defoliation and consequential loss of yield. PGRO trials have shown a 40% yield loss when the disease is left untreated.”

He advised growers to include a rust-active fungicide early-on in the spray programme. “As disease pressure is so high, even in spring beans, a two-spray programme will be needed in many situations.”

Products such as the firm’s Signum (pyraclostrobin + boscalid) and Caramba (metconazole) were particularly suited to high-risk rust situations, while Walabi (pyrimethanil + chlorothalonil) offered an alternative in low to moderate disease situations, he said.