Diversity of fungal pathogens in leaf spot disease of Indian mulberry and its management

Abstract

Leaf spot disease in mulberry significantly affects silk production by reducing the nutritive quality of the leaves. This disease caused by various pathogens, regardless of the localities under the same climatic region. In the present investigation, an approximate incidence rate of 84 % was recorded in Karnataka based on surveys conducted in both farmer fields and germplasm locations. The causative agents have shown diversification, including new candidates such as Bipolaris sorokiniana, Curvularia lunata, Cladosporium sphaerospermum, and Epicoccum sorghinum. These findings mark the first report of these pathogens in Indian mulberry production. The investigation involved detailed pathogenicity assessments on the predominant mulberry silk production cultivar under controlled and field environments. Pathogens were identified using morpho-cultural, microscopic and phylogenetic analyses, including the internal transcribed spacer (ITS). Various concentrations of fungicides, both individually and in combinations, were evaluated to identify effective measures for mitigating yield losses. Among the fungicides tested against the new pathogens, Hexaconazole 5 % SC and Hexaconazole 5 % + Captan 70 % WP demonstrated high promise and cost-effectiveness. Consequently, these fungicides could serve as immediate solutions to prevent further yield reduction. However, it is essential to conduct comprehensive field investigations before recommending them as standard practices. Future research endeavors should focus on assessing the extent of crop loss caused by these newly identified pathogens in mulberry cultivation.