Survey and symptomatology of false smut [Ustilaginoidea virens (Cooke)Takahashi] of rice

 

*Ankit K Chaudhari, Kalubhai B Rakholiya, Mulji D Jehani

Department of Plant Pathology, N. M. College of Agriculture, Navsari Agricultural University, Navsari-396 450 (Gujarat) *Corresponding author Email: ankit.nau2009@gmail.com

Volume 14(1), 2021              Click here for Pdf

Received: 16th March 2021; Accepted: 19th May 2021

Abstract

 

False smut of rice is one of the major emerging and destructive diseases especially in high yielding rice varieties of many rice growing regions of the India. False smut disease infection may initiate at the booting/ flowering stage and visible symptoms appear at the grain filling stage. For tracking the disease status, we undertook a survey to assess the disease incidence and severity levels in the rice growing areas of South Gujarat. Rice growing areas viz., Navsari, Surat, Valsad, Tapi and Dang and NAU farm were surveyed at grain maturity stage during the kharif 2017 and kharif 2018. In a random survey, two villages were selected in each district and per cent disease incidence, average smutted ball per panicle and disease severity index were recorded in each season. During field visits, we also recorded the symptoms of false smut on the basis of changing the colour of smut balls. Among the eleven surveyed locations, Jamalapada recorded maximum per cent disease incidence i.e., 12.15, 10.06 and 11.11 during 2017, 2018 and mean of two years, respectively. The maximum average smutted ball per panicle recorded was 2.80 per cent in Jamalapada, during 2017 and 2.52 per cent in Khatal, during 2018, while the mean maximum average smutted ball was 2.63 per cent in Jamalapada. Maximum disease severity index, observed in Jamalapada was 34.02, and 24.65 and during 2017 and 2018, respectively with a mean of 29.15. Infected spikelets of the panicle transformed into yellowish-orange to olive-green colour smut ball, almost double the size of the normal rice grains and unfertilized florets infection led to the production of chaffy grains. In severe cases, complete chaffy panicles with numerous smut balls were observed.th