Albert Lea Seed House Oat Production Guide | Page 12

Plant Disease
Monitoring disease pressure is just as important in oats as any other crop. A handful of diseases bring about the largest share for concern. Crown and stem rusts, Septoria, and Fusarium Head Blight are the most prominent fungal diseases. These can all be treated with timely applications of fungicides in a conventional cropping system. In an organic
system, control comes from genetic resistance which increases the importance of variety selection and early planting.
Barley yellow dwarf or Red leaf is a prominent virus that can affect oats. The best management plan for this disease is
genetic resistance and/or chemical control of the Cherry Oat Aphid, which is a vector for the virus.

Crown Rust

Crown rust is one of the most common and destructive diseases of oat plants in North America. This disease is
caused by the fungus Puccinia coronata f.sp. avenae. The risk of Crown rust, like most fungal diseases can increase
greatly with warm and humid weather with ample moisture. Moderate to severe epidemics can reduce grain yield by
10 to 40% (USDA ARS Crown Rust). Damage can increase as the disease moves up the plant to the flag leaf. Infection
of the flag leaf greatly reduces the photosynthetic activity of the plant. This is known to reduce the number of kernels, their size and test weight. Fields should be scouted during the late 4-leaf stage and into flag-leaf.
Symptoms
The fungal disease can be seen on the top and bottom of infected leaves (Fig. x1). An infection will form a yellow-orange colored pustule. As the infection continues they will begin to turn black as the teliospores are formed within
the pustule (Fig x2). The pustules can be found on any leaf of the plant and can move to the leaf sheaf during heavy
infections.

Fig. x1. Early symptoms of crown rust on oats lower leaves.

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