Survey of fungicide sensitivity in Colletotrichum gloeosporioides from different avocado and mango production areas in South Africa

Pre-harvest fungicidal treatments aimed at reducing inoculum levels in the field include copper oxychloride and benomyl. Pre-harvest applications of b enomyl are currently restricted if used on fruit destined for certain expor t markets. Isolates of Colletotrichum gloeosporioides collected during a th ree-year market survey were used to determine the incidence of resistance t o benomyl, thiabendazole and prochloraz using an in vitro assay. A total of 17.7% of all isolates tested were resistant to benomyl, of which 8.5% were highly and 9.2% moderately resistant. Isolates from certain production are as were less sensitive to benomyl and thiabendazole, and mango isolates wer e generally more sensitive than avocado isolates. No isolates were resistan t to thiabendazole or prochloraz.