Infection results in a rather moist light brown rot which shows many light pink pustules on the surface.
Spots are small at first, later enlarge and become covered by the small spore-producing pustules.
Large areas may be affected, sometimes destroying entire plants. No satisfactory control is available, other than removing and destroying diseased cladodes as soon as noticed. In the greenhouse, soil from infected plants should be removed and benches disinfected. Spraying with a copper fungicide may help in checking the disease. Charcoal spot is a common and destructive disease of Opuntia in Texas.