Agriculture: Small Grains Pest Management Guidelines

Leaf Blotch of Oats

  • Pyrenophora avenae
  • Symptoms and Signs

    This disease appears as reddish tan leaf blotches that are somewhat linear with irregular margins. Heavily infected leaves die. Seedling blight may occur if coleoptiles are infected.

    Comments on the Disease

    The fungus survives on infected, undecayed plant debris in soil or less commonly inside the hull of infected seed. The disease is favored by cool and rainy weather.


    No specific control is necessary in California. Practices that control other diseases, such as the use of clean seed, crop rotation, and elimination of crop residue, help control leaf blotch as well.

    Text Updated: 02/07