Anthracnose in açaí palm leaves reduces photosynthesis by affecting gas exchange and chlorophyll a fluorescence. The study measured changes in photosynthetic performance in leaves infected with Colletotrichum sp. The infected plants showed decreased CO2 assimilation, stomatal conductance, transpiration, and chlorophyll levels, while intercellular CO2 concentration increased. Chlorophyll a fluorescence decreased starting at 3 days after infection, affecting various parameters like photochemical efficiency and electron transfer rate. Overall, the infection reduced the plant's ability to capture light and assimilate CO2, leading to a decrease in photosynthetic capacity.