Myriangiales

Myriangiales is an order of fungi within the class Dothideomycetes. In agronomy, these fungi are recognized as specialized pathogens or epiphytes that primarily affect woody plants. They are characterized by the development of complex, multilocular stromata that embed themselves into the host plant's tissues, often causing persistent, crust-like lesions on the surface of bark or foliage.

The causal agents are ascomycete fungi that interact with the host by colonizing the epidermal layers. This type of disease is often chronic, as the fungus slowly draws nutrients from the plant. Unlike fast-acting necrotrophs, members of Myriangiales may coexist with the plant for extended periods before causing visible structural damage to the xylem or phloem tissues.

The host range is primarily focused on fruit trees and decorative woody species. Citrus trees and certain pome fruits are particularly susceptible to infections within this order. The pathogen is often found in regions with humid climates, where it can colonize various parts of the plant, including stems, leaves, and fruits, interfering with the plant's overall development and harvest quality.

Common symptoms include the appearance of dense, blackish, or brownish scab-like structures that are tightly adhered to the plant surface. As the infection progresses, the area around the stroma may become necrotic, leading to the cracking of bark and the distortion of leaves or fruit surfaces. This severely impacts the aesthetic and commercial value of the agricultural production.

Disease development is highly favored by prolonged humidity and lack of air circulation within the canopy. To protect crops, it is essential to implement strict sanitation practices, including the removal and destruction of severely infected branches. Chemical control involves the application of broad-spectrum fungicides during the dormant season, complemented by proper orchard hygiene and balanced fertilization to ensure the host remains vigorous and resilient.