Epichloe baconii

Epichloe baconii is a fungal endophyte that causes a significant condition in perennial grasses known as "choke disease." As an ascomycete fungus, it establishes a systemic relationship with the host plant, colonizing the intercellular spaces. While some endophytes are beneficial to plants, E. baconii is specifically noted for its pathogenic interference with the plant's reproductive structures.

The host range of Epichloe baconii primarily involves various species of bentgrass (Agrostis). The fungus integrates into the plant's growth cycle, ensuring that it is passed on to the next generation of plants via seed transmission. This vertical transmission is a critical factor in the persistence and spread of the disease within agricultural landscapes and natural meadows.

The diagnostic symptom of the infection is the formation of a stromatal sheath around the developing flower stem. This fungal stroma acts as a physical barrier, preventing the inflorescence from emerging from the leaf sheath. Consequently, the affected tillers fail to flower, resulting in complete seed sterilization and stunted development of the affected grass shoots.

The environmental development of the fungus is highly dependent on humidity and seasonal temperatures. The asexual stage (conidial) is often spread by insects visiting the grass florets, which facilitates cross-fertilization of the fungus between different plants. Once established in a population, the infection can spread horizontally through these insect vectors, increasing the disease incidence in a field.

Damage caused by Epichloe baconii is most severe in seed production fields where the loss of inflorescences leads to direct yield reduction. Management strategies focus on proactive measures:

• sourcing pathogen-free certified seed,
• removing and destroying infected plants to reduce inoculum levels,
• implementing mowing schedules to disrupt the life cycle of the fungus before conidial production reaches its peak.