Corynespora cassiicola (Berk. & MA Curtis) CT Wei (1950)

Corynesporiose (target spot)

General

• Fungus fairly widely distributed throughout the world, reported in several tropical or humid subtropical countries in America (United States, Brazil, Mexico, etc.), Europe (Romania, etc.), Africa (Nigeria, etc.), India, from Asia (Japan, Taiwan…) and the Caribbean (Cuba, Puerto Rico, Haiti, Trinidad…). One of the major pathogenic fungi of tropical and subtropical zones.
• Disease observed in the open field as well as under shelter.
• Extremely polyphagous, affecting more than 145 botanical genera belonging to at least 53 families, including several vegetables.

• Susceptible botanical family(s):

• All symptom photos  (web only)

Biology

• Conservation : is maintained and multiplies on a wide variety of cultivated plants (pepper, eggplant, tobacco, melon, cucumber, certain beans, hydrangea, soya, rubber, sesame, cotton, etc.) or weeds ( Commelina benghalensis , Vernonia cinerea , Aspilia africana , Lepistemon sp., etc.). Can easily be preserved on plant debris for more than 2 years, through its mycelium and its chlamydospores.
• Infection : contaminates vegetables during wet periods, via the stomata or directly through the cuticle, and rapidly colonizes the tissues.
• Sporulation : forms many characteristic elongated spores on damaged tissues (Figures 1 to 4).
• Dissemination : spores dispersed by wind and air currents, rain and splashes.
• Favorable conditions : heavy rains, long periods of humidity and temperatures of around 24 to 31°C (thermal optimum: 28°C).

Protection

• Carry out crop rotations , without involving sensitive crops .
• Avoid setting up new plantations near affected or susceptible crops.
• Eliminate old diseased leaves at harvest time, do not leave them on the ground.
• Use resistant varieties , mainly in cucumber.
• Fungicides ) can be applied preventively during periods of risk ( ephy , or as soon as you observe the very first symptoms.