Fusarium circinatum (Nirenberg and O’ Donnell) is the causal agent of pine pitch canker (PPC) disease, one of the most devastating forest diseases worldwide. Long-distance spread occurs mainly through the movement of infected seeds whereas at regional level, the movement of seedlings, substrates, or containers may play an important role in fungal dispersal. Invasion of nurseries takes place via infected seeds and further spread can occur by planting contaminated seedlings, especially due to the possibility of infected plants remaining symptomless. Once established, F. circinatum spreads by rain, wind, and insects. The natural spread of the pathogen is limited due to the short dispersal distances of the spores and the fairly short flight distances of disseminating insects. In this review, we summarize the currently known dispersal pathways of the pathogen, discussing both natural and human-assisted processes. With the purpose of understanding how to best intervene in the disease’s development in nurseries and forests, we outline the epidemiology of the pathogen describing the key factors influencing its spread. Preventive measures to control the spread of F. circinatum locally and globally are described with special emphasis on the challenges in implementing them.

Bark beetles (Coleoptera, Scolytinae) carry a diverse filamentous fungal community sometimes acting as vectors or carriers of phytopathogens. In this study, mycobiota carried by two Tomicus species (Tomicus piniperda and Tomicus destruens) were investigated through (i) morphological and molecular identification of taxa; (ii) taxonomic richness, diversity, evenness, dominance and phoresy indices; (iii) ecological network analysis and (iv) statistical co-occurrence analysis. The studied mycobiota were formed by eleven taxa and showed a moderate fungal diversity with low evenness. The fungus Sydowia polyspora was significantly abundant and dominated the community. All the fungal taxa were randomly associated. Both insect species (T. piniperda and T. destruens) were collected from plantations of Pinus radiata infected by Fusarium circinatum. The ecological factors that could drive community ecology and phoretic links between fungi and bark beetles are discussed.

Fifteen families of mycoviruses have been described and 80% of these catalogued. However, their evolutionary relationship with fungi is not clear. The mycovirus genome can be formed by single- or double-stranded RNA or single-stranded DNA. The effects of mycoviruses range from the induction of a cryptic state (asymptomatic) to promotion of hyper- or hypovirulence in the host. Horizontal transmission of mycoviruses is determined by the presence of different vegetative compatibility types and mating types. Biocontrol of chestnut blight (Cryphonectria parasitica) has been found to be a successful mycovirus-based treatment and is considered a model in forest disease management. Development of this type of biological control tool for use in other forest pathologies requires a sound knowledge of viral symptomatology and transmission. The present review focuses on the application of mycoviruses and the prospects for future use in the biological control of forest diseases as well as on advances in mycovirus-applied research in forestry, landscape and culture of woody plants.