Barley growers with crops that have a history of leaf spotting should be prepared to apply treatments before symptoms appear, the Home Grown Cereals Authority has advised.
The disease, caused by ramularia, poses greatest threat to spring barley in northern Britain, but can occur UK-wide, said the HGCA’s Graham Jellis.
“Prevention with fungicides is most effective when applied at boot stage (GS45-49), provided applications are made before symptoms appear, usually after the crop has flowered.”
He suggests a mixture of either prothioconazole or epoxiconazole with chlorothalonil. Growers could also consider a Qol (strobilurin) fungicide as a partner for broad-spectrum disease control.
Spring barley varieties differ in their resistance to ramularia, but none are fully resistant, he says. Optic can be worst hit, with yield losses up to 0.9t/ha, while Decanter typically looses 0.1t/ha. The average yield loss in high risk sites is 0.4t/ha.
Information on how to control the disease can be found in a new topic sheet at www.hgca.com