Paraboeremia selaginellae

The fungal pathogen Paraboeremia selaginellae is the causal agent of a specific leaf spot disease in Selaginella species. This pathogen is a member of the Ascomycota phylum and is known for its ability to colonize the moist, humid environments required by its host plants, eventually causing tissue necrosis and decay.

The primary hosts for this disease are plants from the genus Selaginella. Given their popularity as ornamental ground covers in terrariums and greenhouses, the pathogen can cause significant damage in dense plant populations where air circulation is limited and moisture levels are consistently high.

Symptoms of the infection typically begin as small, discolored spots that gradually enlarge and transition to a brownish or blackish hue. As the infection progresses, the tissues may become necrotic and brittle. Under microscopic examination, small black fruiting bodies known as pycnidia can be observed emerging from the affected necrotic tissue, which release spores to facilitate further spread.

The development of the disease is heavily dictated by environmental factors. High relative humidity and prolonged leaf wetness provide the necessary conditions for spore germination and colonization. Transmission often occurs through water splashes, contaminated soil media, or infected propagation material, making strict hygiene protocols essential in controlled environments.

The impact of Paraboeremia selaginellae includes severe loss of aesthetic value and, in untreated cases, the complete senescence of the plant. Prevention involves improving ventilation to reduce humidity and ensuring that foliage remains dry whenever possible. When an outbreak is confirmed, targeted application of appropriate fungicides, combined with the removal of symptomatic plant material, is the most effective management approach.