Botryobasidium pruinatum

Botryobasidium pruinatum is a basidiomycetous fungus recognized in plant pathology for its role in causing cortical decays and necrotic lesions on various plant species. While primarily functioning as a soil-inhabiting saprotroph, it under favorable environmental conditions acts as a latent pathogen, compromising the structural integrity of the host plant.

The host range of this pathogen includes a variety of woody shrubs, ornamental trees, and certain perennial herbaceous plants. It is particularly hazardous in nurseries and dense plantations where moisture levels remain consistently high throughout the growing season, facilitating the colonization of the host's lower stems and root collar area.

Symptoms often begin with a thin, whitish to grayish mycelial web spreading across the bark. As the infection progresses, the underlying tissue undergoes degradation and softening, often turning necrotic. This localized decay impairs nutrient and water translocation, leading to premature leaf drop, chlorosis, and in severe cases, the death of the entire branch or plant.

The development and spread of Botryobasidium pruinatum are heavily dependent on environmental conditions, particularly high humidity, poor air circulation, and shaded environments. The fungus spreads via basidiospores that are easily dispersed by water splash, wind, or contaminated agricultural tools during routine maintenance tasks.

Management strategies focus on preventing the establishment of the fungus through improved cultural practices. This includes increasing plant spacing to promote airflow, keeping the root collar area dry, and prompt removal of diseased debris. Chemical control via fungicides should be targeted at the base of the plant during periods of high humidity to effectively suppress sporulation and prevent further disease progression.