Phyllachora

Phyllachora is a genus of fungi belonging to the order Glomerellales and the family Phyllachoraceae. These fungi are primarily known as plant pathogens, causing a variety of diseases on a wide range of host plants. The most characteristic symptom of Phyllachora infection is the development of black, stroma-like structures on the leaves, stems, or other aerial parts of the host. These stromata, often referred to as "tar spots," are typically embedded within the plant tissue and contain the fruiting bodies of the fungus.

The life cycle of Phyllachora species often involves both asexual and sexual reproduction. Asexual spores, known as conidia, are produced within the stroma and aid in the rapid spread of the fungus during the growing season. Sexual spores, ascospores, are produced in asci within the stroma and are important for long-term survival and genetic recombination, often overwintering on infected plant debris.

Species within the Phyllachora genus exhibit a broad host range, affecting grasses, legumes, and various other herbaceous and woody plants. Examples of diseases caused by Phyllachora include tar spot of corn ( Phyllachora maydis ), tar spot of bluegrass ( Phyllachora poae ), and various leaf spots on legumes. While many Phyllachora species are considered significant pathogens, others may exist as endophytes with limited or no observable negative impact on their hosts. The exact ecological role and host specificity of many Phyllachora species are still areas of ongoing research. Identification of Phyllachora species typically relies on morphological characteristics of the stromata, spores, and host plant associations.