Diaporthe perniciosa a species of fungus in the family Diaporthaceae. It is a plant pathogen.
The names Phoma prunorum Cooke, Phomopsis prunorum (Cooke) Grove, and Phomopsis mali Roberts have been used for its asexual (anamorph) form.[1]
It causes bark cankers on trees in the genera Malus (apples), Pyrus (pears) and Prunus (plums, cherries, peaches and other similar fruits).[2] 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.[3]