EPIDEMIOLOGICAL STUDY OF FALSE SMUT OF RICE (ORYZA SATIVA L.) IN GUJARAT

Rice false smut [Ustilaginoidea virens (Cooke) Takahashi] is an upcoming major disease in India. The initiation of the disease was recorded the 88th day after sowing and 9th September in 2017 and 86th day after sowing and 14th September in 2018. The incidence of false smut starts from 1.55 percent at 36 MSW and reached to 7.22 percent at 42 MSW in 2017 while, 0.53 percent at 37 MSW and reached to 6.68 percent at 42 MSW in 2018. However, in pooled of two years, the first symptom of false smut was recorded on 36 MSW (0.77 %) and reached to 42 MSW (6.95 %). Correlation coefficient study between weather parameters and disease incidence indicated that all the parameters jointly played an important role in the development of false smut disease. Moreover, maximum and average temperature, morning and average relative humidity, morning and average cloudy weather and sunshine hours were found to play important role in the disease development. Stepwise regression, R-value i.e., 0.89, 0.80 and 0.75 percent and co-efficient of determination, R2-value i.e., 79.90, 64.70 and 56.90 percent were found high during 2017, 2018 and pooled of two year, respectively. These high R-value indicating a strong association between percent disease incidence to weather parameters