Department of Plant Pathology, CSKHPKV, Palampur-176062
National Symposium on Strategic Issues in Plant Pathological Research held at Department of Plant Pathology, CSK HP Krishi Vishvavidayalaya, Palampur on November 24–25, 2011
Rice leaf scald pathogen Rhynchosporium oryzae was found to grow and sporulate on temperature ranging from 15 to 30°C under in vitro conditions but the optimum temperature range for growth and sporulation was 25–30°C. Pot experiment under controlled conditions showed that relative humidity greatly affects the disease incidence and severity. High incidence was found at RH > 70 per cent whereas severity was maximum above 80 per cent RH. Under field condition the weather parameters were found to affect only the establishment of infection as disease appeared in the field between second fortnight of August to first fortnight of September when all the weather parameters were optimum for the establishment of infection. Negative correlations were obtained between all the studied weather parameters viz. maximum, minimum and average temperature, RH, rainfall and rainy days whereas apparent infection rate ‘r’ was found to be positively correlated with varoius weather parameters except maximum temperature. Highest positive correlation value of ‘r’ was obtained with rainy days favouring the dispersal of leaf scald pathogen in the field through water splashes.
