Biology, epidemiology

Corynespora cassiicola is extremely polyphagous, which allows it to maintain and multiply on a wide variety of cultivated plants (pepper, eggplant, tobacco, melon, cucumber, certain beans, hydrangea, soya, rubber, sesame, cotton, etc.) or weeds ( Commelina benghalensis , Verronia cinerea , Aspilia africana , Lepistemon sp., etc.) which ensure the multiplication of this fungus and act as reservoir plants. It keeps easily on plant debris for more than 2 years. Contamination takes place during humid periods, via the stomata or directly through the cuticle. Once in the tissues, the fungus rapidly colonizes them and sporulates on the altered tissues (Figure 1), forming characteristic elongated subhyaline to slightly brown conidia, isolated or in short chain (Figure 2). These have 4 to 20 pseudo-partitions (figure 3). They are dispersed throughout the morning by wind, rain and splash. They ensure secondary contamination.

This fungus is favored by heavy rains, long periods of humidity and temperatures in the range of 24 to 31 ° C. Its thermal optimum would be around 28 °