Epidemiology and management of aromatic rice blast incited by Pyricularia oryzae Cavara
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Date
2022-07
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CCSHAU Hisar
Abstract
Rice (Oryza sativa L.) is an important staple food crop feeding more people directly than any other crop in the world. More than 70 diseases have been reported in rice. Out of these, rice blast is the most ravage disease incited by Pyricularia oryzae acting as a major impediment in rice production. In favourable conditions, this disease can devastate entire rice plant in vegetative stage giving a burnt appearance and cause yield losses up to 90%. The present investigations were conducted on various aspects of blast disease like screening of promising genotypes for rice blast resistance, role of weather parameters in disease progression and evaluation of different botanicals and suitable fungicides. Role of weather parameters in disease progression was recorded in 2 varieties CSR 30 and HBC 19 and the results revealed that temperature (maximum and minimum), rainfall and rainy days were negatively correlated and relative humidity (morning) was positively correlated with percent disease index of leaf blast. For neck blast incidence weather variables temperature (maximum and minimum), rainfall, rainy days and relative humidity (evening) were negatively correlated. In vitro evaluation of botanicals was conducted against P. oryzae, Achook @ 4ml/lt and Garlic @ 5% were found to be effective with 100 per cent inhibition of mycelial growth of pathogen. The concentrations with maximum mycelial inhibition were evaluated under field conditions, Achook @ 4ml/lt proved to best in controlling leaf and neck blast with increased yield as compared to control. Field trials were conducted on the variety CSR 30 for the evaluation of different fungicides at Rice Research Station, Kaul (Kaithal) during kharif 2021. Among six different fungicides evaluated under field conditions, picoxystrobin 6.78% + tricyclazole 20.33% SC was found to be best in controlling leaf and neck blast and also increased yield as compared to control. Forty-seven rice genotypes were screened for neck blast resistance, four genotypes were susceptible with disease rating scale of 7 and forty-three genotypes were highly susceptible with disease rating scale of 9.