Rigidoporus ulmarius

Rigidoporus ulmarius is a species of fungus in the family Meripilaceae. It is commonly known as the Elm Bracket or Elm Fungus, and is a wood-decay fungus that primarily affects elm trees.

Description

Rigidoporus ulmarius is a large, perennial polypore that forms semicircular or fan-shaped fruit bodies. The upper surface is smooth and white to cream in color, often with a pink or orange tint. The underside is white and features small, round pores. The flesh is white, tough, and fibrous.

Distribution and Habitat

Rigidoporus ulmarius is widely distributed across the Northern Hemisphere, particularly in Europe and North America. It is commonly found on dead or dying elm trees, but can also infect other hardwood species. The fungus prefers temperate climates and is often found in forests, parks, and urban areas with mature trees.

Ecology

Rigidoporus ulmarius is a saprophytic fungus, meaning it feeds on dead or decaying organic matter. It plays a crucial role in the ecosystem by breaking down the tough cellulose and lignin in wood, recycling nutrients back into the soil. However, it can also act as a pathogen, infecting and killing living trees.

Impact on Elm Trees

Rigidoporus ulmarius is one of the main causes of white rot in elm trees. The fungus invades the tree through wounds in the bark, then spreads through the wood, causing it to become soft and spongy. This weakens the tree and can eventually lead to its death. The disease is particularly devastating for mature elm trees, which are a significant feature of many urban landscapes.

Control and Management

Control of Rigidoporus ulmarius involves a combination of preventative measures and active management. Regular inspection of trees for signs of infection, prompt removal of infected wood, and proper wound care can help prevent the spread of the fungus. In some cases, fungicides may be used to treat infected trees.

See Also

• Dutch elm disease
• Fungi of Europe
• List of Meripilaceae species