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 [...] delicate, simple morphological features hence is not easy to place it at the generic level. Årsvoll was the first to identify and describe the fungus in Norway [...] -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 extend only to 2 mm