Fungal diseases of grapevine in Morocco: current knowledge, limitations, and future perspectives

Grapevine diseases are a major limitation to viticulture in Morocco, where various climatic conditions favour the development of leaf, fruit, trunk, and soil-borne pathogens. This review synthesizes historical and recent information on major fungal grapevine diseases in Morocco, focusing on their distribution, epidemiology, diagnostic methods, and management challenges. Downy mildew, powdery mildew, and gray mold continue to have a high economic impact through leaf and fruit infections, leading to intensive fungicide use, while grapevine trunk diseases, particularly Botryosphaeria dieback (caused by Botryosphaeriaceae fungi), are increasingly responsible for yield losses. Although chemical control usage has increased in Morocco, disease management remains primarily focused on preventive methods, which are often suboptimal as they are not guided by forecasting models or integrated with biological control. Furthermore, historical data indicate a previous reliance on symptomatic diagnosis, which has led to gaps in the molecular diagnostic capacity needed for accurate assessment of pathogen diversity and emergence. Finally, this review identifies critical research gaps in Moroccan viticulture, including the lack of national monitoring programs, insufficient experimental validation of biological controls in the field, and the inadequate adoption of climate-informed management practices.