The order Diaporthales is a group of fungi within the class Sordariomycetes (phylum Ascomycota) that primarily includes plant-associated species, many of which are important pathogens, endophytes, or saprobes. Members of Diaporthales are characterized by producing perithecial (flask-shaped) fruiting bodies with unitunicate asci and often elongated, septate ascospores. Several species in this order, such as those in the genus Diaporthe, are notorious for causing cankers, dieback, and other diseases in crops and forest trees. They exhibit diverse life strategies, ranging from latent infections in living plants to decomposition of dead plant material, and they are widely distributed across temperate and tropical regions. This order is of significant ecological and economic importance due to its impact on agriculture and forestry.