Impact of Varying Sowing Dates, Fungicides and Bio Formulations on Development of False Smut Disease of Rice

Background: Rice false smut caused by Ustilaginoidea virens has been considered as most serious grain disease throughout the world. In recent times, the disease has been observed to show an increasing trend in rice fields of Assam, India. Methods: The present investigation was conducted at Assam agricultural University, Jorhat, India during kharif 2018 and 2019. The experiment was laid out in a randomized block design with an aim to study the effect of different dates of sowing, fungicides and bioformulations on management of false smut of rice under field condition. Result: Among different date of sowing, highest incidence of false smut (21.55%) and severity (75.06%) with lower grain yield (28.98 q/ha) were recorded in late sown crop (9th July) which flowered during last week of October. The crop sown on 10th May, when the crop flowered during last week of August to first week of September showed lower disease incidence (4.98%) and severity (4.76%) with higher grain yield (35.94 q/ha). Propiconazole (0.1%) as two foliar application (at booting stage and flowering stage) effectively controlled rice false smut disease with a significant reduction of disease severity (91.93%) and increased grain yield up to 18.63 per cent over control. Among the bioformulations, Taegro Eco (Bacillus based) was found to be highly effective next to chemicals in controlling rice false smut with a reduction of disease severity (74.94%) and enhanced grain yield up to 11.40 per cent over control. The study suggests that early sowing with foliar application of fungicide, propiconazole is an effective management strategy for rice false smut.