Bark-beetle outbreaks and associated fungal infections have resulted in the death of massive numbers of Pinaceae trees in the American west. The main focus of our research was to identify bark-beetle fungal symbionts collected from piñon trees (Pinus edulis) in New Mexico. Approximately 20 bark beetles including adults, larvae and pupae were collected from trees at the Sevilleta National Wildlife Refuge in central New Mexico. Surface sterilized and non-surface sterilized beetles were plated on 2% MEA with antibiotics. DNA from fungal isolates was extracted, amplified, and sequenced using fungal specific nrITS primers. Fungal collections were stored in mineral oil.
Results/Conclusions
More than 100 fungi were isolated from Ips confusus. Although isolates included several P. edulis fungal endophytes, the majority were Ophiostomatoid fungi closely related to Ophiostoma montium and O. ips from Mexico and Graphium sp. from Ips perturbatus (the northern spruce engraver) from western Canada. Ophiostoma was isolated from internal bark beetle tissues, as well as external segments such as wings, legs, heads, and abdomens. Ophiostoma was also found in all the developmental stages: larvae, pupae and adults. A large number of Ophiostomatoid fruting bodies were observed in beetle galleries. The characterization of plant pathogens associated to bark beetles is necessary to understand the widespread drought–related tree mortality documented for this species.
