Fruit infection by Colletotrichum gloeosporioides and anthracnose resistance of some mango cultivars in Thailand

Infection of mango fruit cv. Nam Dok Mai by Colletotrichum gloeosporioides was studied using artificial inoculation. Under optimum conditions (95 - 100% RH, 25 degreesC), germination and appressorium formation started at 12 h and 14 h, respectively, after deposition of conidia on the peel. After 48 h, 60% of fungal propagules present were appressoria. The fungus could infect mangoes through both pedicel and peel wounds, causing stem end rot and anthracnose in ripe fruit. Inoculation of wounded peel resulted in symptom development in unripe fruit whereas unwounded peel showed no symptoms. Resistance of fruits to disease depended on cultivar. Testing of fruit resistance to the fungus could be conducted by inoculation of fruit at 24 h after harvesting. When inoculated at both pre- and post-harvest stages, mango cvv. Nam Dok Mai, Nang Klang Wan and Chok Anan were found to be susceptible to anthracnose whereas Rad and Kaew were relatively resistant.