Powdery Mildew - Barley

Blumeria graminis

Powdery mildew is a common parasitic fungus of barley. Powdery mildew is commonly found in the base of crops but it can develop to infect the entire canopy. Initially seen as surface patches of white mycelium, powdery mildew develops to cover the entire leaf. Mature infections often have black spore cases present. The disease is windborne and thrives in cool, wet weather. While normally modest, significant yield losses have been recorded.

Powdery Mildew Barley — Spring barley crop affected with a severe powdery mildew infection.

Look out for:

Surface patches of white mycelium
Black spores

Risk factors:

Cool, wet weather
Dense crop canopies

Related Pests

Scald

Rhynchosporium secalis

Scald (Rhynchosporium secalis) is a common disease of barley which can result in significant yield loss if not controlled. Scald is favoured by cooler, moist conditions with the initial source of inoculum being infected straw debris. The first symptoms often appear during winter or early spring, initially as pale greyish lesions which then develop a more straw coloured appearance with a defined dark edge to the lesion.

Ramularia Leaf Spot

Ramularia collo-cygni

Ramularia leaf spot (Ramularia collo-cygni) is a common disease of barley which can result in significant yield loss if not controlled. While both winter and spring planted barley can be affected, the impact of Ramularia is usually greater on winter planted crops. Ramularia is seed borne and once the fungus has infected the plant it grows within the plant, not producing visible symptoms until around ear emergence. Symptoms consist of small brown lesions which under the right conditions can rapidly increase and coalesce together.

Net Blotch

Pyreophora teres

Net blotch (Pyreophora teres) is a common disease of autumn sown barley (much less commonly spring sown barley) which can result in significant yield loss if not controlled. Charateristics net type lesions give the disease its common name but lesions can also take the form of dark stripes and streaks and when infection is severe in large dead areas of leaf. Infection sources are either seed or crop debris, which is borne out by second year barley crops being likely to carry infection. Net blotch development is favoured by cool, moist conditions.