Few lesions per leaf.

Moderate number of lesions per leaf below ear.

Numerous lesions on leaves below the ear - but no evidence of lesion coalescence.

Numerous lesions with some killing of patches of leaf tissue below the ear.

Whole leaves killed up to the ear and some disease evident above the ear.

Heavy disease over whole plant - some leaves above the ear severely infected.

Heavy disease over whole plant and some leaves above the ear killed.

All leaf tissue above ear nearly completely diseased.

Plants dead.