Mungbean yellow mosaic virus (MYMV) causes yellow mosaic disease in pulses. Which is most serious disease in greengram, blackgram and many pulses growing areas of North Eastern Karnataka region. The reasons for its higher incidence can be known by studying its epidemiological factors. Hence, the study was carried on epidemiology of MYMV. Epidemiological investigations involve study of weather factors, pathogen, its vectors if any, and host factors. In the present study, epidemiology of MYMV vector whitefly was investigated with weather factors like minimum temperature (0c), maximum temperature (0c), rainfall (mm), minimum relative humidity (%), maximum relative humidity (%) wind speed (Km/h) and sunshine (hours) recorded daily at MARS, Raichur. In the present study, whitefly population was greatly influenced by environmental factors which prevailed during entire observation period of one year stating from 22nd SMW of 2016 to 21st SMW of 2017. The least whitefly population was observed during 40th SMW (16/trap) and 39th SMW (20/trap) when the weekly mean maximum temperature was 28.90C and 30.4 0C, minimum temperature was 22.8 0C to 22.2 0C and total weekly rainfall was 60.8 mm for 4 days respectively. The highest number of whiteflies was noticed during 50th SMW (1456/trap) when maximum temperature was 29.7 0C, minimum temperature was 16.7 0C and rainfall of 8.2 mm. This indicates that decrease in whitefly population was mainly due to higher rainfall and lower minimum temperature, whereas, increase in whitefly population was due to higher maximum temperature and no rainfall. Correlation and regression analysis was done to know the relationship of weather parameters with whitefly population. Results revealed that, there was a negatively significant correlation between whitefly population and minimum temperature (r= -0.354) and positive significant correlation with maximum temperature (r= 0.250) was recorded. Correlation of whitefly with rainfall was negatively significant (r= -0.456) while other factors like relative humidity (minimum and maximum), sunshine hours and maximum wind speed showed nonsignificant correlation with whitefly population. Sunshine hours recorded shown positive relation with whitefly population (r= 0.631). Regression analysis showed that, all these weather factors were found to contribute up to 69.6 percent towards the whitefly population and obtained multiple regression equation.

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