Widespread distribution. Citrus species. A 'cosmetic' disease. Fungal spots on fruit and leaves; on fruit, unsightly and affects quality. Unlikely to reduce yield unless severe on leaves and blocks sunlight.
Spots, black, circular, on upper and lower surfaces, up to 5 mm diameter. More spots on densely shaded trees.
Spores from the black spots spread by wind during wet or humid weather.
Cultural control: prune trees after main harvest removing unhealthy, unwanted and poorly positioned branches, and to improve air movement so that leaves and fruit dry faster; avoid shade of taller trees.
Chemical control: use horticultural oil. Try also white oil, or soap solution (see Fact Sheet no. 56).