Molecular characterization of Neopestalotiopsis spp. (grey leaf spot disease) on Persea bombycine hook (Som plant) in Assam, India

Northeast India, particularly Assam, is a significant region for sericulture, home to the renowned Muga silkworms (Antheraea assamensis Helfer) that produce golden-hued silk. The primary feeding plants for these silkworms are Som (Persea bombycine King ex Hook. Fil. Kosterm) and Soalu (Litsea monopetala Juss). However, these plants are susceptible to diseases, including grey leaf spot, which affect leaf quality and silkworm productivity. This study aimed to identify the pathogen causing grey leaf spot on Som plants. Diseased leaf samples were collected from various locations in Assam, and fungal isolates were designated and analyzed using PCR with ITS-1 and ITS − 4 primers. The isolate BP2, identified through sequence analysis and BLAST^®, showed the highest homology (92.6%) with Neopestalotiopsis spp. strain NTUCC (accession number MT322112). The results were submitted, and the accession number OQ195903 was assigned by NCBI. Pathogenicity tests also confirm the pathogenic effect of the test isolate BP2. This study provides crucial insights into the pathogen responsible for grey leaf spot, aiding in developing management strategies for sericulture sustainability.