Chocolate spot and rust warning for bean growers

With an abrupt end to a long period of dry, almost drought-like conditions, growers need to take every possible precaution to protect beans from chocolate spot and rust infections.

That is the warning from Adama’s fungicide expert, Andy Bailey, who advises that the ongoing wet weather conditions could put both winter and spring bean crops at risk of infection from bean chocolate spot (Botrytis spp.).

“Winter sown beans are typically protected against chocolate spot with a two-spray programme starting at the early flowering stage, usually in early May,” Mr Bailey explains. “This year the weather was dry during that period so crops weren’t under too much pressure. For spring beans, fungicide treatments are yet to get underway, but that doesn’t mean growers should be complacent: the onset of wetter conditions could spell trouble as there is an increased potential for the disease to develop in both crops.”

Rust in beans.

Mr Bailey also warns that bean crops could come under significant pressure from rust infections once the current spell of wet weather comes to an end and temperatures start to rise.

For effective protection against both diseases, Mr Bailey recommends Custodia: “Applied at between 0.75 and 1.0 litres per hectare depending on the level of disease pressure, Custodia uses a combination of tebuconazole and azoxystrobin to provide curative and protectant activity against both diseases.  Ideally positioned as part of a programme at the late flowering stage/early pod set, Custodia provides robust protection against chocolate spot and rust, as well as aiding green leaf retention to the benefit of yields.”