Identification and pathogenicity of Graphium and Pesotum species from machete wounds on Schizolobium parahybum in Ecuador

Schizolobium parahybum is native to Ecuador and is widely distributed throughout South America. This tree has ideal timber properties and is a favored species for plantation development. Schizolobium parahybum trees, however, suffer from a serious disease that causes substantial losses to plantations in Ecuador. Most diseased trees have been regularly wounded with machetes and it has been suggested that these wounds might provide entry portals for pathogens. To determine the possible role that fungi associated with machete wounds might play in disease development, wood samples were taken from these wounds and screened for possible pathogens. A number of potential pathogens were identified, including Ceratocystis fimbriata, C. moniliformis, Graphium spp. and Pesotum spp. The objective of this study was to identify the twenty-one synnematous Hyphomycetes, from wounds on S. parahybum, using small subunit (SSU) and internal transcribed spacer (ITS) sequence data from the ribosomal RNA operon. We also investigated the possible role of these species in disease development in a greenhouse inoculation trail. Results showed that fifteen isolates reside in the Graphium penicillioides complex (Order: Microascales). Four isolates resided in the Ophiostomatales and represent the Pesotum anamorph of Ophiostoma quercus. The remaining two isolates were unidentified Pesotum anamorphs of Ophiostoma. None of the three species produced significant lesions in a greenhouse inoculation trail and we do not consider them pathogens of S. parahybum.