Citrus black spot
This Ascomycete fungus affects citrus plants throughout subtropical climates, causing a reduction in both fruit quantity and quality. Symptoms include both fruit and leaf lesions, the latter being critical to inter-tree dispersal. Strict regulation and management is necessary to control this disease since there are currently no citrus varieties that are resistant.
Leaf symptoms are only noticeable on highly susceptible citrus plants; lemons in particular. The symptoms generally develop from latent infections after the leaves have died. Red-brown, pin-point dots may develop into larger, circular necrotic lesions with gray centers and red or brown margins.