Cyclaneusma needle cast

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Cyclaneusma needle cast Cyclaneusma minus

Cyclaneusma needle cast (Cyclaneusma minus ) Symptoms on jack pine.jpg

Cyclaneusma needle cast is a fungal disease that affects pine trees, particularly species within the genus Pinus. The disease is caused by the fungus Cyclaneusma minus, which leads to the premature shedding of needles, impacting the overall health and growth of the affected trees.

Symptoms

The primary symptom of Cyclaneusma needle cast is the yellowing and browning of needles, which eventually leads to needle drop. Infected needles typically show symptoms in late summer or early fall. The disease can be identified by the presence of small, black fruiting bodies called ascocarps on the surface of the needles. These fruiting bodies release spores that spread the infection to other needles and trees.

Life Cycle

The life cycle of Cyclaneusma minus involves the production of ascospores within the ascocarps. These spores are released during wet weather conditions and are dispersed by wind and rain to new host needles. The fungus can infect needles at any time of the year, but symptoms usually become visible in the late summer or fall. The disease can persist in fallen needles, which serve as a source of inoculum for new infections.

Host Species

Cyclaneusma needle cast primarily affects pine species, including:

• Pinus radiata (Monterey pine)
• Pinus nigra (Austrian pine)
• Pinus sylvestris (Scots pine)

Management

Management of Cyclaneusma needle cast involves several strategies:

• Cultural practices: Removing and destroying fallen needles can help reduce the source of inoculum. Thinning dense stands of trees can improve air circulation and reduce humidity, which can help limit the spread of the disease.
• Chemical control: Fungicides can be applied to protect new growth from infection. The timing of fungicide applications is critical and should be based on local disease forecasts and environmental conditions.
• Resistant varieties: Planting resistant or less susceptible species of pine can help reduce the impact of the disease.

Impact

Cyclaneusma needle cast can significantly impact the health and productivity of pine forests and plantations. Severe infections can lead to reduced growth rates, increased susceptibility to other diseases and pests, and in extreme cases, tree mortality. The disease is of particular concern in commercial forestry operations where it can lead to economic losses.

See also

• Fungal diseases of plants
• Pine
• Forest pathology