Anisogramma anomala

Anisogramma anomala is an ascomycete fungus within the Gnomoniaceae family that serves as the causal agent of Eastern Filbert Blight. Belonging to the kingdom Fungi and phylum Ascomycota, this obligate pathogen is a major limiting factor for hazelnut production. It targets specifically the Corylus genus, posing a severe threat to both commercial orchards and wild hazelnut populations.

The primary symptom of the disease is the development of linear, raised, black fungal stroma that rupture the bark of branches and trunks. As the infection progresses, the fungal mycelium colonizes the cambium layer, causing localized necrosis. This results in the disruption of nutrient and water transport, eventually leading to dieback of limbs above the cankerous growths and tree mortality.

The biological life cycle of Anisogramma anomala typically spans two years. Initial infection of new shoots occurs in the spring, but the visible signs of the fungus do not appear until the following year. As the pathogen matures, it produces perithecia that release ascospores during wet, rainy conditions, which are then disseminated by wind and rain splashes to new, susceptible tissue.

Environmental conditions play a critical role in the epidemiology of the disease. High humidity and rainfall are essential for spore release and infection success. Given that young shoots are the most susceptible, early spring weather is a high-risk period for orchard infection. The fungus thrives in climates where extended periods of moisture persist throughout the budding and shoot elongation phase.

Effective control requires an integrated approach to orchard management. Key strategies include:

• Systematic pruning of infected limbs, cutting well below the visible cankers.
• Selecting and planting resistant cultivars, which is the most effective long-term solution.
• Applying protective fungicides during the period of spore dispersal.
• Monitoring nursery stock closely to prevent the introduction of the pathogen into new areas.