Barley Stripe, Fungal Stripe

Pyrenophora graminea (asexual Drechslera graminea)

Biology

Barley stripe can cause significant yield losses in barley, other cereals are not affected.

This fungus is exclusively seed-borne and overwinters on or in the seed. The fungus grows internally within the infected plant. Spores are produced on the infected leaves and are spread by wind to nearby healthy heads. The seeds become infected only in the field and are most susceptible during early development of the seed head.

Infection of seedlings is higher when soil temperatures remain below 15 degrees Celsius. Sporulation on the foliage of infected plants is encouraged by high humidity.

Damage Description

Vivid longitudinal yellow stripes bounded by the veins appear on the leaves and extend from the base of the leaf to the tip. The stripes eventually become brownish and infected leaves characteristically tear and fray. Infected plants are stunted and heads become twisted, blighted or fail to emerge.

The yield loss is directly proportional to the percentage of infected plants. A 1 per cent infection causes a 0.7 per cent direct yield loss. Some crop compensation occurs from neighbouring healthy plants.

Diagnosis

Infected plants are most obvious just before heading out, and the disease can be readily identified at this time. After heading out, infected plants may be "lost" under the canopy. Seed samples may be sent out to Agriculture Canada Seed Laboratory in Ottawa to determine the percentage infection.

Management Strategy

• Use disease resistant varieties.
• Avoid infested seed.
• Use a fungicidal seed treatment

Fungus stripe visible in infected barley crops from the seedling stage to heading out. Plants with striped leaves are scattered here and there throughout the crops indicating seedborne nature.

Barley leaves showing fungus stripe - looks similar to bacterial leaf stripe and net blotch but both these diseases occur in patches or over the whole field.

At head emergence the fungus stripe infected plant may die. The infected leaves split along the stripes and the head fails to fill. Fungus spores are scattered at this stage to healthy barley heads when they lodge in or on the seed coats. After heading out the diseased plants are "lost" under the canopy.