''Diaporthe perniciosa'' 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 ...

in the family Diaporthaceae. It is a

plant pathogen Plant diseases are diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like orga ...

. The names ''Phoma prunorum'' Cooke, ''Phomopsis prunorum'' (Cooke) Grove, and ''Phomopsis mali'' Roberts have been used for its asexual (anamorph) form. It causes bark

canker A plant canker is a small area of dead tissue, which grows slowly, often over years. Some cankers are of only minor consequence, but others are ultimately lethal and therefore can have major economic implications for agriculture and horticultur ...

s on trees in the genera ''

Malus ''Malus'' ( or ) is a genus of about 32–57 species of small deciduous trees or shrubs in the family Rosaceae, including the domesticated orchard apple, crab apples (sometimes known in North America as crabapples) and wild apples. The genus i ...

'' (apples), ''

Pyrus Pears are fruits produced and consumed around the world, growing on a tree and harvested in late summer into mid-autumn. The pear tree and shrub are a species of genus ''Pyrus'' , in the family Rosaceae, bearing the pomaceous fruit of the sa ...

'' (pears) and ''

Prunus ''Prunus'' is a genus of flowering plant, flowering trees and shrubs from the family (biology), family Rosaceae. The genus includes plums, cherries, peaches, nectarines, apricots and almonds (collectively Drupe, stonefruit). The genus has a cosm ...

'' (plums, cherries, peaches and other similar fruits). It has also been implicated in dieback disease of plums. One study in the late 1980s was able to isolate the fungus from several trees with die-back symptoms but inoculation of healthy trees with the fungus did not result in disease.

References

perniciosa Fungi described in 1921 Fungal plant pathogens and diseases Fungus species {{Fungus-plant-disease-stub