Prospecting and Identification of Fungi Associated with the Rice Leaf Scald Disease in Togo

Abstract

Leaf scald, caused by Rhynchosporium oryzae, is the third most damaging rice fungal disease worldwide after blast and helminthosporiosis. This study presents the first report of leaf scald on rice in Togo, based on a comprehensive survey of 93 rice plots across 28 out of 39 prefectures. The research aimed to identify, characterize, and test the pathogenicity of fungi associated with leaf scald symptoms, as well as determine the disease's distribution and severity in Togo. Samples were collected, processed in the laboratory, and cultured using blotting paper and potato dextrose agar media. Results revealed that 97,84% of surveyed plots exhibited symptoms related to leaf scald and severity of the disease record were most 5 except two plots which were recorded 9 on the scale of 1 to 9. Fungal isolates were confirmed as R. oryzae through macroscopic and microscopic analysis, adhering to criteria described in existing literature. Growth of mycelium where about 7,5 days in 90 mm petri dish from both paper blotting and PDA medium from initiative culture. Sporus where two or three septa and were obtained after 9 days. Koch's postulates were fulfilled by reproducing leaf scald symptoms using the isolated fungi on the variety IR 841 at 50 days stage. This study contributes valuable insights into the prevalence and characteristics of leaf scald in Togolese rice field.