How to recognize and combat fruit anthracnose

Colletotrichum sp. is a genus of phytopathogenic fungi comprising numerous species capable of causing disease in a wide variety of crops, especially fruits. Many species exhibit hemibiotrophic behavior, initiating colonization of living tissues relatively discreetly and subsequently progressing to a necrotrophic phase in which they destroy cells and cause visible lesions. The fungus develops a mycelium composed of hyphae that can grow on the surface and penetrate tissues. An important characteristic of many Colletotrichum species is the formation of specialized structures called appressoria, which allow the fungus to adhere firmly to the plant surface and exert mechanical pressure and enzymatic activity to penetrate the cuticle and access internal tissues. Infection can occur through directly penetrable tissues, although wounds, cracks, insect damage, and other lesions considerably facilitate pathogen entry. After becoming established, the fungus may initially remain inconspicuous, especially when the fruits have not yet reached maturity. As the infection progresses and the fruit ripens, the pathogen's activity may increase and become evident through the appearance of characteristic necrotic lesions. Acervuli, reproductive structures in which numerous conidia are produced, form in the affected areas. Conidia are generally hyaline and unicellular and constitute one of the main sources of pathogen propagation. When environmental conditions are favorable, conidia can germinate on the fruit surface and form germ tubes and appressoria. Surface moisture is especially important for germination and penetration to occur. Conidia can be released from the lesions by water and subsequently reach other susceptible fruits or tissues. Rain, sprinkler irrigation, water splash, tissue contact, and cultivation practices can all promote their dispersal. The pathogen can also survive between growing seasons in infected plant debris, affected fruit, and other contaminated materials, providing sources of inoculum for new infections. In certain species, infections can remain latent for a significant portion of fruit development and manifest themselves later during ripening or after harvest. This characteristic is especially relevant in fruits intended for storage and sale, since a fruit that appears healthy at harvest time can develop lesions during transport or storage.