Management of false smut of rice caused by Ustilaginoidea  virens (Cke.) Tak.

Preeti

Management of false smut of rice caused by Ustilaginoidea virens (Cke.) Tak.

Date

2023-02-08

Authors

Preeti

Publisher

CSK HPKV, Palampur

Abstract

False smut of rice caused by Ustilaginoidea virens (Cke.) Tak. is an emerging production constraint in rice growing regions of India and Himachal Pradesh. The investigation on “Management of false smut of rice caused by Ustilaginoidea virens (Cke.) Tak.” was undertaken during 2020-22 in the Department of Plant Pathology, CSKHPKV, Palampur and RWRC, Malan. The pathogen was confirmed as Ustilaginoidea virens on the basis of its morphological and cultural characteristics. Systematic surveys were conducted in different rice growing areas in eight districts of State showed that false smut incidence varied from 0.2 to 55.5 per cent during kharif-2022. The incidence of false smut was the highest at Rampur (55.5%) followed by Surajpur (45.5%), Dhaulakuan (40.5%) and Puruwala (40.0%) of district Sirmour, while it was the least in district Shimla. The relation between disease incidence and weather variables was non-significant in all date of sowing except in 2nd date of sowing i.e. 5th June with maximum temperature. Disease incidence was comparatively higher in 21st May sown crop than in 5th June and 20th June sown crop The coefficient of determination (R2 ) revealed that selected weather variables i.e. temperature and relative humidity contributed 72.8, 95.3 and 99.8 per cent towards incidence of false smut on the crop sown at 21st May, 5th June and 20th June, respectively. Out of sixty one genotypes, seventeen genotypes (HPR 3236, HPR 3239, HPR 3243, HPR 3248, HPR 3250, HPR 3251, HPR 3253, HPR 3254, HPR 3260, HPR 3261, HPR 3262, PB 1121, Kasturi, HPR 2612, HPR 3228, HPR 3218, HPR 3226) showed highly resistant reaction, seven (HPR 3256, HPR 3259, HPR 2929, HPR 3213, HPR 3211, HPR 2703, HPR 2696) resistant, twenty three moderately resistant, five moderately susceptible while all the nine hybrids (Arize 6129, Arize 6444, Arize Swift, AZ 6508, BS 10008, DR 8101, PAC 834, PAC 807 Plus, Arize 6129 Gold (Check) showed susceptible reaction. In vitro evaluation of fungicides showed a complete inhibition of mycelial growth of the pathogen with propiconazole (Tilt 25 EC), tebuconazole (Folicur 250 EC), tebuconazole 50% + trifloxystrobin 25% WG (Nativo 75 WG), mancozeb 63% + carbendazim 12% WP (Companion) and mancozeb (Indofil M-45) at different concentrations ranging from 25-1000 ppm. However, under field conditions, application of two sprays of propiconazole 25 EC one at booting stage and second 10 days later proved to be the most effective resulted in the maximum (51.94%) reduction in disease incidence with highest grain yield of 57.95 q/ha and provided 28.46 per cent increase over control followed by two sprays of tebuconazole 50% + trifloxystrobin 25% WG registering around 50 per cent reduction in disease incidence with 24.60 per cent increase in grain yield over control. Two sprays of propiconazole 25 EC also provided the maximum reduction in smut ball formation (97.34%) followed by two sprays of tebuconazole 50% + trifloxystrobin 25% WG (96.76%).