Disease is favored by cool temperatures and moist conditions. Therefore, more common and severe in wheat sown in the fall. Entire seed is replaced by lack fungal spores. Disease is favored by cool to moderate temperatures and humid conditions.
Infections only occur during flowering.
Click on an image to display it in larger detail. S. nodorum lesions are round. Cool, wet, windy weather favors S. tritici development. Warm wet weather favors S. nodorum . Infected crop residues, seed, voluteer wheat, some grassy weed hosts.