Pathogenicity and epidemiology of Corynespora cassiicola in the Republic of Seychelles

Abstract

Corynespora cassiicola is reported in the Republic of Seychelles, where it causes a leaf spot disease of tomatoes, cucumbers and watermelons. Isolates from tomatoes and cucumbers were cross pathogenic, but differences in symptoms indicated a degree of host specificity. The fungus developed rapidly as a saprophyte and sporulated abundantly for at least 28 days on dead tomato leaves in the field. Numbers of conidia increased with duration of wetting of the debris. C. cassiicola colonized and sporulated on papaya leaf debris. Isolates from papaya leaf debris caused leaf lesions on tomato, cucumber and watermelon, but isolates pathogenic on papaya were not found. C. cassiicola is an aggressive facultative parasite that sporulates abundantly on plant debris. Inoculum of C. cassiicola from several sources can initiate disease cycles. Consequently, sanitation as a control measure appears to be justified.