Abstract:
Anthracnose disease of grapevines, historically attributed to Elsinoe ampelina, has emerged as
a significant concern in the Jaffna Peninsula, Sri Lanka. This study aimed to characterize the
disease’s etiology, epidemiology, and potential for biological control. Field assessments over
two cultivation seasons (2022–2023) revealed a consistent pattern of disease progression, with
peak incidence and severity occurring between 40 and 60 days post-pruning. Rainfall positively
correlated with disease metrics, while wind speed showed a suppressive effect. Morphological
and cultural characterization of 54 fungal isolates, coupled with multilocus phylogenetic
analysis (ITS, actin, and histone H3), confirmed the presence of two distinct Colletotrichum
morphotypes within the C. gloeosporioides species complex, potentially representing a novel
lineage. Pathogenicity assays verified the virulence of representative isolates on grape leaves
and fruits under both in vitro and in planta conditions. Furthermore, spore germination and
lesion development were significantly inhibited by cell-free suspensions from Pseudomonas
fluorescens, Bacillus megaterium, and ethanol extracts of Azadirachta indica, Lantana camara,
Vitex negundo, Stoechospermum marginatum, and Padina boryana. These findings establish a
members of new lineage of C. gloeosporioides complex as the primary causal agent of grape
anthracnose in the region and highlight the promise of integrating biocontrol agents and
botanical extracts into sustainable disease management programs.
