First Report of Alternaria jacinthicola Causing Leaf Blight on Macaranga peltata From India

Macaranga peltata (Roxb.) Müll. Arg., a tropical tree widely distributed in South and Southeast Asia, is an ecologically and economically important species used for timber, traditional medicine, afforestation and agroforestry. During seedling evaluations at the College of Forestry, Thrissur, Kerala, India, characteristic symptoms of leaf blight were observed. A fungal isolate was consistently recovered from diseased tissues through standard tissue isolation methods. Cultural and morphological characteristics, together with multi‐gene phylogenetic analyses comprising the internal transcribed spacer (ITS), Glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH), the translation elongation factor 1‐alpha region (TEF1α) and Alternaria major allergen gene (Alt a 1), confirmed the pathogen as Alternaria jacinthicola . The pathogenicity of the isolate was validated through inoculation studies by fulfilling Koch's postulates. The present investigation constitutes the first confirmed report of Alternaria jacinthicola causing leaf blight on Macaranga peltata in India. Since A. jacinthicola is expanding its host range and posing a new threat to tropical forest nurseries, foresters need to implement regular monitoring and adopt suitable management interventions.