Integrated strategies for the containment of Gnomoniopsis castaneae in chestnut orchards of the Campania region

Gnomoniopsis castaneae is an emerging fungal pathogen causing significant damage to chestnut (Castanea sativa) pro- duction in southern Italy, particularly in the Campania region. This study focused on strategies for monitoring, controlling, and mitigating the spread of the pathogen within chestnut orchards. Integrated management approaches, including phy- tosanitary practices, pruning, removal of infected plant mate- rial, and application of biological and chemical treatments, were evaluated under laboratory and field conditions. Sen- sitivity baselines were constructed for 80 isolates on 4 com- mercial formulations, relating to 4 categories of fungicides: “biological” (copper oxychloride; Eugenol + Geraniol + Thy- mol); triazoles (Tetraconazole); sterol biosynthesis inhibitor in fungi (Fenhexamid); inhibitor mitochondrial respiration (Boscalid). In 2024, the incidence of G. castaneae was moni- tored in chestnut orchards in the Campania region following the application of the most effective active substances iden- tified through in vitro assays. Treatments were integrated with rational and sustainable agronomic practices. In 2024, although disease pressure was relatively low, a 6% reduction in the incidence of G. castaneae was recorded in chestnut trees treated with four of the tested active substances (copper oxy- chloride, Eugenol + Geraniol + Thymol, Tetraconazole, Fen- hexamid). These preliminary results support the potential of selected compounds to contribute to disease mitigation, even under less favorable conditions for pathogen development. The aim was to evaluate the field performance of selected compounds within an integrated disease management frame- work under real cultivation conditions. The results of this study indicate that, beyond sound agronomic practices, ratio- nal orchard management—such as the removal of infected plant material and the application of effective phytosanitary treatments—can play a key role in reducing the impact of G. castaneae and enhancing disease control in chestnut orchards.