Root rot of carrot
the disease forms circular to irregular spots on the leaves that vary in colour from grey to almost black. The spots appear to be sharply defined, but under [...] temperatures ranging from -3°C to 25°C, with an optimum around 18°C. Lesions are dark brown to black, moist, mostly circular spots 0.5 -1.2 cm diameter that [...] leaf will die off. The fungus appears to prefer older tissue. In the field, the disease is difficult to distinguish from both Cercospora and Alternaria dauci