Diaporthe ambigua  

Description contributed by Graham Kinsey, CABI.

Causing circular to fusoid pustulate ruptures of host periderm which are often laterally elongated, bark surface irregularly blackened.

Anamorph: Phomopsis ambigua (Sacc.) Traverso (1906). Conidiophores to 20 x 1-2.5 µm. Alpha-conidia 7-10 x 2-4 µm; beta-conidia 15-36 x 1-1.5 µm.

Teleomorph: Ascomata scattered irregularly or crowded in bark or wood, ostioles erumpent singly or in small clusters and stout or slightly elongated. Ascospores 11-14 x 2.5-4 µm.

Wehmeyer considered this to belong within the D. eres aggregate.