Lemon-yellow hymenogaster

Hymenogaster citrinus is a species of sequestrate fungus belonging to the family Hymenogastraceae. While it is naturally found in forest ecosystems as a mycorrhizal partner, in agricultural and forest nursery settings, it can act as a stressor, interfering with the physiological health of young seedlings.

The fungus is primarily a soil-dwelling basidiomycete. Its role as a disease agent is typically opportunistic, occurring when the balance of the rhizosphere is disrupted, leading to competitive exclusion or direct damage to the delicate root structures of developing crops.

This fungus predominantly affects the root systems of coniferous species and certain hardwoods. Symptoms include stunted growth, chlorosis, and the appearance of thick mycelial mats covering the roots, which physically block the uptake of essential soil nutrients and water, ultimately weakening the host plant.

Development is favored by cool, moist conditions and high organic content in the soil substrate. The fungus spreads via spores in the soil profile and through water transport, making it particularly problematic in nurseries with poor drainage systems and consistent moisture levels.

Effective management strategies involve rigorous substrate sterilization, improved irrigation scheduling to avoid waterlogging, and maintaining soil pH levels that are suboptimal for rapid fungal spread. Integrated pest management, focusing on biological soil balance, remains the best preventative approach.