Plant Disease Management Handbook

Cause Verticillium dahliae, a fungus widespread in soil and that affects a wide range of herbaceous and woody plants. The fungus gains entry through the root system; progress in the plant is primarily through the vascular system. Cool, moist soil favors the disease.

Symptoms Leaves turn yellow and dry up. Wilting progresses up the plant until the plant dies. A cross-section of a node near the plant base may reveal discolored vascular tissue.

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Cause A fungus, Ustilago avenae, carried on seed.

Image related to Oats (Avena sativa)-Loose Smut

Cause Pyrenophora avenae (asexual: Drechslera avenae; syn. sexual: Helminthosporium avenaceum; asexual: D. avenaceum), a fungus that overwinters on old straw or stubble.

Cause Manganese deficiency. The problem is localized mostly in areas in northern and extreme eastern Idaho.

Symptoms Light green to gray-brown spots and streaks develop mainly on leaves. Plants may be greatly reduced in height and yield. The entire plant may be yellow if the condition is severe.

Cultural control Apply 3 lb/A manganese to foliage or 15 to 25 lb/A manganese sulfate to soil.

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Cause Ustilago segetum (= U. kolleri), a fungus carried on seed.