In Florida, anthracnose is one of the most severe mango diseases. The most serious consequences of anthracnose are observed in regions where it rains throughout the flowering and fruiting periods of mango. Colletotrichum gloeosporioides is the fungus responsible for mango anthracnose. The formation of spores by this fungus is enhanced when the weather is wet or humid. Rain and wind are two natural forces that help spread these spores across the environment. Because of this, the disease is capable of spreading across relatively short distances. Anthracnose can destroy inflorescences and infect and drop immature fruit in wet regions where it is common during flowering and fruit set. It should come as no surprise that this could result in significant losses. There is evidence that the anthracnose fungus can cause latent infections. This indicates that the fungus can infect green fruit and lay latent inside, emerging when the fruit reaches full ripeness. The physiological changes associated with ripening can reactivate the anthracnose fungus, leading to the formation of lesions and eventual rotting of the fruit.
Typically, leaf spots occur near the edges of the leaf. They range in shade from light tan to deep brown, and frequently have a darker edging. Emergence of new leaf flushes during wet periods increases the risk of infection. Infections like these typically manifest as semicircular lesions on the margins of young, golden or pale green leaves. Defoliation of young shoots and a dark affected patch on newly emerging twigs are both possible outcomes of prolonged exposure to high humidity. Anthracnose causes big, sunken, black lesions on newly produced fruit, and the infected fruits eventually fall off the plant. Quite a large, green, and medium Large, shiny, black, and sunken lesions characterize the young fruit damaged by anthracnose. These fruits are prone to cracking and oozing. Depressed grey-black patches on the skin of ripening fruit are the characteristic of the most common fruit anthracnose, which is caused by latent infections (as mentioned above). Spore masses, often pink to orange in color, grow on this tissue throughout time.
Copper fungicides sprays, which are advised for the treatment of mango scab, are effective against anthracnose. Copper fungicides should be sprayed on trees on a regular basis from when flowers begin to form in order to limit the prevalence of infection in the developing fruit.
More information: https://edis.ifas.ufl.edu/publication/MG216