Cercospora Early Blight are small yellow spots, visible on both sides of the leaf, are the first symptom of early blight, that grow into grey, circular lesions. As leaf spots dry out, the tissue becomes papery in texture and often splits and cracks. Elongated lesions may develop on petioles. Under favourable conditions, the lesions will coalesce and cause a blighting effect on the leaves. Cercospora apii is a seed borne pathogen and may also survive in the field on celery debris. Spores are spread via wind and splashing water.