Pestalotiopsis glandicola

Pestalotiopsis glandicola is a pathogenic fungus that causes significant necrotic diseases in various woody and ornamental plant species. As an agronomically relevant pathogen, it primarily affects host tissues by destroying cell structures, leading to premature wilting, discoloration, and eventual necrosis of leaves, shoots, and fruit components.

The host range of Pestalotiopsis glandicola includes diverse groups of plants, specifically targeting Fagaceae species like oaks, as well as a variety of coniferous trees such as thuja, juniper, and cypress. The fungus acts as a secondary invader or a primary pathogen depending on the vigor of the plant, often exploiting vulnerabilities caused by environmental stress or inadequate cultural management.

Symptoms of the disease are characterized by the appearance of dark, sunken lesions on the leaves or needles, often surrounded by a chlorotic halo. As the infection progresses, the tissues become necrotic and brittle. One of the most distinct diagnostic features is the development of small, dark, fruiting bodies (acervuli) on the surface of the lesions, which release masses of spores under high humidity conditions.

The proliferation of this fungus is heavily dependent on moisture. Wet, humid conditions combined with mild temperatures create an ideal environment for spore germination and colonization. Wind and splashing rain are the primary agents of dispersal, carrying spores from diseased twigs to healthy foliage and branches throughout the planting site.

Effective management strategies require an integrated approach focusing on sanitation and preventive chemical treatment. Removing and destroying infected plant material is crucial to reduce the inoculum level in the garden. Applying fungicides during the early spring or periods of high humidity helps prevent new infections, while optimizing plant health through proper fertilization and watering minimizes the susceptibility of the plants to the pathogen.

• Pruning infected branches and disposing of debris.
• Sterilizing pruning tools between uses to prevent cross-contamination.
• Applying fungicides during the growing season as a preventive measure.
• Ensuring adequate tree spacing to promote air circulation.