Boeremia exigua var. exigua

(Ascochyta nicotianae)

Boeremia exigua var. exigua (formerly Ascochyta nicotianae, the pathogen of "ragged leaf spot") is a fungus causing circular greyish to beige spots (figures 1-4). It can affect the plant at all stages of development. This fungus produces particular structures on spots, such as black pycnidia, which can be seen with careful observation.
 
This pathogen is widespread. It has already been reported in several European countries but not recently in France. The use of systemic fungicides containing dithiocarbamate antimildiou, could be the reason of its near extinction in France.
 
For more information on this foliar parasite, see the corresponding fact sheet, Boeremia exigua var. exigua (Phoma exigua var. exigua)