Pathogenicity and Virulence of Botrytis galanthina Causing Gray Mold on Snowdrop in Ornamental Production

Abstract

Gray mold symptoms observed on snowdrop (Galanthus nivalis L.) cultivated under ornamental production systems were investigated to determine the pathogenicity and virulence of Botrytis galanthina. Field observations revealed water-soaked lesions on leaves and floral tissues, followed by rapid tissue collapse and characteristic gray sporulation under cool and humid environmental conditions. Fungal isolates obtained from infected plant parts produced fast-growing, gray to brown colonies with abundant conidiophores and branched clusters of conidia typical of Botrytis species. Pathogenicity assays conducted under controlled environmental conditions successfully reproduced gray mold symptoms on healthy snowdrop plants, confirming the causal role of B. galanthina and fulfilling Koch’s postulates. Virulence assessment indicated variation in lesion expansion rates and disease severity among isolates, suggesting differential aggressiveness within field populations. Microscopic examination confirmed profuse conidial production on necrotic tissues, facilitating secondary spread under high humidity. Molecular confirmation using ITS rDNA sequencing supported identification of isolates as Botrytis galanthina, with phylogenetic placement within the Botrytis cinerea species complex, indicating close evolutionary relationships with other gray mold pathogens. Environmental factors such as prolonged leaf wetness, low temperature, and dense canopy conditions were strongly associated with increased disease development and severity. The study highlights the susceptibility of ornamental snowdrop production systems to gray mold infection and emphasizes the epidemiological risk posed by B. galanthina under protected and open-field cultivation. These findings underscore the need for integrated disease management strategies, including sanitation, environmental regulation, and judicious fungicide application to minimize disease impact in ornamental horticulture systems.