Fungal Diversity, Pathogenic Characteristics and Fungicide Sensitivity of Pathogens Isolated from Areca catechu L. Diseases in Hainan Island

Abstract

This study systematically identified the pathogenic fungi affecting Areca catechu in Hainan. Using diseased tissues from five regions, isolates were obtained using molecular methods, and their pathogenicity was confirmed using Koch’s postulates. We obtained 44 distinct fungal isolates from 9 genera. Fusarium (27.27%) and Colletotrichum (38.12%) were the dominant genera across all tissues. Twenty isolates were confirmed as pathogens. Key findings include the first report of Alternaria angustiovoidea and A. pogostemonis as areca leaf spot pathogens in China and the first confirmation of pathogenicity for three Fusarium species complexes (FSSC, FFSC, FIESC). Five Fusarium species are newly reported as pathogens in China. Cladosporium tenuissimum and Plectosphaerella cucumerina were confirmed for the first time to cause leaf spot. Fusarium, Colletotrichum, and Alternaria were core pathogens, all exhibiting high polygalacturonase and cellulase activity. The FFSC and Colletotrichum gloeosporioides species complex (CGSC) showed broad-spectrum pathogenicity on tropical fruits. Fungicide sensitivity assays ranked efficacy as prochloraz > difenoconazole > tebuconazole > ethylicin > pyraclostrobin, with genus-specific responses observed. This research fills a systematic knowledge gap on areca fungal diseases in China, providing a crucial basis for precise control strategies and integrated management.