First report of Curvularia lunata (ON246070) causing leaf spot disease of banana from Raiganj, West Bengal, India

Abstract

Between December 2021 and January 2022, leaf spot disease was observed on leaves of field grown banana plants and the disease was reported from the location of Sarai, Raiganj, Uttar Dinajpur District, West Bengal. The temperature ranged from 10.3-17.8 °C in December and 9.0-24.0 °C in January. Symptoms first appeared as yellowish brown spots throughout the middle portion as well as around the margin of leaves. Lesions often have a brown border and can be surrounded by a yellow halo. Symptoms ranged from a few lesions scattered across leaves to lesions densely covering large sections of leaves. The diseased leaf sample (1-1.5 cm) was cut into small pieces and transferred into PDA (Potato Dextrose Agar) medium after surface sterilization of the leaf sample with 0.1% HgCl2 for 2 min, followed by ethanol for 2 min. A fungus was isolated from the infected leaf onto potato dextrose agar amended with antibiotic Monocef. The fungus was characterized morphologically using microscopes and identified as Curvularia lunata using molecular techniques (As per Light microscopic and scanning electron microscopic views of mycelia and conidia of the fungus). Based on molecular identification (18S rDNA partial sequencing), the fungus was identified as Curvularia lunata (ON246070) and finally submitted to NCBI GenBank. Disease symptoms were developed within 5 days on inoculated detached leaves. In detached leaf inoculation technique, on inoculated leaf surfaces, conidial germination was observed after 24, 48 and 72 hrs. of inoculation of spore suspension (1x103 conidia/ml). Curvularia lunata was reisolated from the developed infected spots.