Rosellinia root rot

Rosellinia quercina is a pathogenic ascomycete fungus known to cause severe root rot in various oak species and other woody plants. This pathogen acts as a soil-borne parasite that colonizes the root cortex, effectively disrupting the vascular system and water uptake of the infected host plant.

The disease primarily targets seedlings and young trees in nurseries and young plantations. While oaks (Quercus spp.) are the most frequent victims of this fungus, it can opportunistically infect a variety of broad-leaved trees under high-stress conditions, making it a concern for foresters and nursery managers globally.

Visible symptoms typically appear as sudden foliage wilting, yellowing (chlorosis), and eventual dieback of the tree crown. Upon physical inspection of the root system, one will observe darkened, necrotic bark patches that feel soft or spongy. In advanced stages, white or dark mycelial mats may be visible between the bark and the wood.

The development of Rosellinia quercina is heavily dictated by environmental factors. High soil moisture, poor drainage, and low aeration are the primary conditions that trigger fungal outbreaks. The fungus persists in the soil through microsclerotia and mycelium, spreading through direct root contact between neighboring plants.

Effective management requires an integrated approach.

• Improve soil drainage to prevent waterlogging.
• Maintain optimal soil pH levels through regular testing.
• Remove and destroy infected root systems to reduce inoculum levels.
• Utilize disease-free nursery stock and maintain wide spacing to minimize root contact.