From: Biological control of Golovinomyces cichoracearum, the causal pathogen of sunflower powdery mildew
Grade | Description | Reaction |
---|---|---|
0 | No symptom of powdery mildew on leaves | Immune (I) |
1 | Small scattered powdery mildew specks covering 1% or less leaf area | Highly resistant (HR) |
3 | Small powdery lesions covering 1 to 10% leaf area | Resistant (R) |
5 | Powdery lesions enlarged covering 11 to 25% leaf area | Moderately resistant (MR) |
7 | Powdery lesions coalesce to form big patches covering 26 to 50% leaf area | Susceptible (S) |
9 | Big powdery patches covering 51% or more of leaf area and defoliation occur | Highly susceptible (HS) |