''Phyllosticta concava'', also known as opuntia dry rot or prickly pear brown spot, is a species of

fungus A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

that infects

opuntia ''Opuntia'', commonly called the prickly pear cactus, is a genus of flowering plants in the cactus family Cactaceae, many known for their flavorful fruit and showy flowers. Cacti are native to the Americas, and are well adapted to arid clima ...

cactus, leaving discolored circular depressions in the pads. The species was first

formally described A species description is a formal scientific description of a newly encountered species, typically articulated through a scientific publication. Its purpose is to provide a clear description of a new species of organism and explain how it differ ...

by the mycologist

Fred Jay Seaver Fred Jay Seaver (14 March 1877 – 21 December 1970) was an American mycologist. He worked at the New York Botanical Garden for 40 years, initially as the Director of Laboratories (1908–1911), then as the Curator (1912–1943), and finally as He ...

in 1922.

References

Botryosphaeriaceae Fungal plant pathogens and diseases Opuntia Fungus species Fungi described in 1922 Taxa named by Fred Jay Seaver {{Dothideomycetes-stub