Agrobase Canada
Alternaria leaf blight
Alternaria carotiincultae

Alternaria leaf blight is caused by the fungus Alternaria dauci and is initially characterized by irregularly shaped, brown spots surrounded by a yellow halo along the margins of leaves.

Alternaria rarely infects the petioles of carrots. If the conditions are good for disease development, the lesions will join together causing the leaflets to shrivel and die appearing as though they are burnt.