Phytophthora in forestry, natural environments, agriculture, and horticulture of the Mediterranean Basin and emerging Phytophthora threats from other regions

Abstract

Phytophthora is one of the most destructive genera of plant pathogens, comprising more than 260 described species, with numerous cryptic and undescribed taxa that remain undetected. These oomycetes cause severe diseases in agriculture, horticulture, forestry and natural ecosystems resulting in major economic losses, altered forest dynamics and biodiversity decline. The Mediterranean Basin is particularly vulnerable to these pathogens, due to high crop diversity, rich endemic flora, intensive plant trade networks, and climatic conditions that favour pathogen establishment and spread. Most damaging Phytophthora species are exotic, introduced primarily through infected nursery stock, contaminated soil or irrigation and river water. Their impacts are also affected by environmental stresses, climate change, intensive cultivation and interactions and connectivity among agricultural, forest and natural landscapes. New diagnostic tools and global surveys have revealed significant and previously undiscovered diversity and ongoing biosecurity risks for these pathogens. Effective management and mitigation require harmonised surveillance systems, robust early detection tools, production of pathogen-free planting material, improved hygiene and cultivation practices, and breeding for host tolerance. These approaches must be integrated within broad landscape-level strategies, to safeguard biodiversity and enhance ecosystem resilience across the Mediterranean Basin ecosystems.