Oat Leaf Spot Information: Recognizing Oat Leaf Spot Symptoms

Crop losses of up to 15% have been reported in some seasons in higher oat growing regions due to oat leaf spot. It is caused by one of three fungal pathogens: Pyrenophora avenae , Drechslera avenacea , Septoria avenae . Although this figure is not high, in commercial and smaller areas, the impact is significant. However, control of oat leaf spot is possible by various means.

Symptoms of oat leaf spot

Fungi are probably one of the most common causes of disease in cereals, such as oats. Oat leaf spot occurs during cold and wet periods.
Oats with leaf spot develop later in the disease, which can damage seed heads. It causes symptoms that begin as leaf spot and progress to the black stem and seed blight stages.
In the early stage, oat leaf spot symptoms only affect the leaves, which develop irregular light yellow lesions. As they mature, they turn reddish-brown and rotten tissue falls off, while the leaf dies. The infection spreads to the stems, and once it has infected the stem, the heads of the stems may become sterile.
In the final stage, dark spots appear. In severe cases, the disease will result in the production of malformed kernels or even kernels with no nucleus at all. Not all spots on oat leaves survive the cereal pest. This will depend on the time of year and prolonged weather conditions that favour fungi and cultural conditions.
After heavy rain, fungal bodies form and disperse with wind or rain. The disease can also be spread through contaminated manure from which the oat straw has been consumed by the animal. Even insects, machinery and boots spread the disease.

Oat Leaf Spot Control

As it is more common in areas of oat stubble, it is more common in areas of oat stubble. The area should not be replanted with oats until the old plant material has rotted. The spot may be sprayed with fungicides early in the season, but if it is detected when disease symptoms have spread to other parts of the plant, they are not effective.
In addition to fungicides or tilling old material, rotational tillage every 3 or 4 years is more effective. There are resistant varieties of oats that are useful for disease control in susceptible areas. Seed can also be treated with EPA-approved fungicides prior to planting. It also seems useful to avoid continuous cutting.
Older plants can also be safely destroyed by burning where reasonable and safe to do so. As with most diseases, good sanitation
and good care can prevent the impact of this fungus.