Myriangiaceae

Myriangiaceae is a family of ascomycete fungi that function as obligate parasites or epiphytes on a wide range of woody plants. These fungi are characterized by the production of loculate stromata, which allow the fungus to become embedded within the host tissue, causing physical and physiological stress to the plant.

These pathogens primarily target various agricultural and ornamental crops, including citrus and other broad-leaved trees. The fungus typically colonizes the bark, twigs, and leaf surfaces, creating a physical barrier that extracts nutrients from the host's epidermal and cortical cells, ultimately leading to significant structural damage.

The primary symptoms of a Myriangiaceae infection include the appearance of thick, black, crust-like stromata on the stems and branches. Infected areas may show bark cracking, tissue necrosis, and localized dieback. In many instances, the fungus thrives in close association with scale insects, where it utilizes their honeydew secretions as a secondary substrate for development.

The spread and development of these fungi are heavily dependent on environmental conditions, particularly high humidity and warm temperatures. Spores are disseminated primarily via wind, splashing rain, or through the movement of associated insect pests across the orchard. Stagnant moisture and lack of canopy light penetration further exacerbate the disease spread.

The economic impact of Myriangiaceae includes reduced crop yield, stunted growth of the host plant, and the potential for secondary infections in necrotic tissues. Integrated pest management strategies are essential for effective control:

• Regular pruning and removal of severely infected branches and twigs.
• Application of copper-based fungicides during the dormant season to manage fungal spores.
• Control of scale insects and other hemipterans to reduce the availability of honeydew.
• Improving orchard hygiene to reduce the primary inoculum reservoir.