Splanchnonema

Splanchnonema is a genus of ascomycetous fungi known for causing bark necrosis and canker-like diseases in various woody plants. These fungi typically colonize the bark and underlying tissues, feeding on the host's nutrients and disrupting the vital flow of water and minerals within the tree, often leading to localized branch death or crown thinning.

The host range of Splanchnonema primarily includes broad-leaved deciduous trees such as maples, planes, and willows. While healthy trees may exhibit some level of resistance, trees weakened by environmental stressors, drought, or prior mechanical injuries are significantly more susceptible to successful fungal colonization.

In terms of symptoms, the disease is characterized by the formation of blackened, erumpent stroma that break through the bark's surface. As the infection progresses, the bark in affected areas becomes brittle, cracks, and may eventually slough off, exposing the underlying woody tissue to further infection by opportunistic decay pathogens.

Development and spread are heavily influenced by environmental conditions, particularly high relative humidity and mild temperatures. Spores are primarily dispersed through wind and rain splash. Once an infection point is established, the fungal mycelium grows within the bark, and under favorable conditions, it will continue to expand throughout the season, causing cumulative damage.

Effective management requires strict sanitation practices. This includes the surgical removal and proper disposal of symptomatic branches to reduce the local spore load. It is essential to disinfect pruning tools with alcohol or a bleach solution between cuts. Maintaining overall tree health through adequate irrigation and nutrient management is the most effective preventative strategy against this and other bark pathogens.