Influence of weather parameters on progress of rust disease severity in pea (Pisum sativum L.)

Abstract

Decision to apply one or more fungicide spray will depend on the risk of rust epidemic in a particular year. Rust epidemic is determined by interaction of three important factors namely, susceptible host, virulent pathogen and the most important i.e. favourable environment for a particular period of time. Therefore, it is necessary to study the correlation between different meteorological parameters and rust severity. Present study revealed that rust dis-ease generally appeared 60 days after sowing and was subsequently increased with a period of time till harvest (4.17 to 64.17 per cent). Disease was observed at a maximum temperature of 16.85 to 24.79áµ’C, 8.09 to 12.27áµ’C minimum temperature, 90.30 to 95.70 percent morning Relative Humidity (RH), 54.80 to 78.40 percent afternoons RH, 0.10 to 5.45mm rainfall and wind velocity of 3.93 to 4.23 km/hr. The correlation between different meteorological parameters and rust severity revealed that per cent disease severity showed highly positive correlation with maxi-mum temperature (r = 0.977), minimum temperature (r = 0.704), rainfall (r = 0.039) and wind velocity(r = 0.093) whereas disease severity show negative correlation with morning(r=-0.925) and afternoon RH (r = -0.926). It was observed that the rust severity is highly influenced by the different weather parameters such as temperature, relative humidity, rainfall and wind velocity. This information will help the researchers in formulating the forecasting model for the rust disease in pea and will also supports farmers in decision making regarding time of occurrence of rust epi-demic and thereby, allow timely scheduling and need based utilization of fungicides accordingly for the management of pea rust.