Abstract: Leaf spot is a common fungal disease that seriously affects crops, resulting in significant economic losses. Pilidium is a dangerous plant pathogen that has a broad plant host spectrum as well as several plant infection parts such as leaves, fruits, and roots. The improbable management of plant diseases and disease control has led to the misuse of chemical pesticides, threatening the ecosystem and human health. Therefore, the identification of pathogens and screening of antagonistic microbial strains towards biological control is the current trend in developing eco-friendly agriculture. In this study, the mold strain MD1 was isolated from leaf spot disease strawberry samples in Da Lat. ITS sequence analysis indicated that this mold belongs the genus Pilidium and was 99.5% identical to P. concavum. In screening test for antifungal effect against Pilidium sp. MD1, 8/50 bacterial strains were shown to have the antagonistic activity, and among those, the strongest strain is D18 . Upon analyzing the macroscopic and microscopic characteristics, the ability to biosynthesize catalase, and the 16S rRNA sequence, the strain D18 is determined to be 100% identical to B. subtilis. In conclusion, The Pilidium sp. D18 is a potential strain for applied research in order to produce bio-control products prevent leaf spot disease on strawberry and other putative plant diseases caused by Pilidium, contributing to the development of sustainable agriculture.

Keywords: antifungal, Bacillus subtilis, Pilidium, strawberry leaf spot