Effect of Weather Parameters on the Seasonal Abundance of Leafhopper, Balclutha hortensis in Groundnut Ecosystem

Field studies were conducted for seven years (1999 to 2005) to study the effect of weather factors on the activity of groundnut leaf hopper, Balclutha hortensis L., during different seasons such as summer, Kharif and Rabi. Multiple regression and correlation analyses were used to determine the most influential variables affecting population development. Results indicated that the timing of peak population densities and peak densities of leafhopper were governed primarily by abiotic factors. B. hortensis population was present through out the year on groundnut and widely fluctuated from season to season. However, the intensity was greater during Rabi followed by Kharif and summer. Correlation studies between weather parameters and B. hortensis population revealed that, sunshine hours and wind velocity showed significant positive correlation (r = 0.195 and 0.293, respectively) during Rabi while the remaining parameters fail to show any significant correlation with the leafhopper population. In summer, minimum temperature, morning and evening relative humidity and wind velocity showed significant negative correlation (r = -0.221, -0.302, -0.205 and -0.194, respectively). During Kharif, minimum temperature, morning and evening relative humidity, rainfall and wind velocity showed significant negative correlation (r = -0.277, -0.37, -0.461, -0.207 and -0.388, respectively) whereas, maximum temperature and sunshine hours showed significant positive correlation (r = 0.477 and 0.487, respectively). The coefficient of determination (R²) between weather parameters and leafhopper population during Rabi, summer and Kharif seasons was found to be 11.39%, 12.01% and 30.19%, respectively over seven years of study suggesting the importance of these parameters in influencing the abundance of B. hortensis.