author(s)
Nistha Rawat, AK Karnatak and RM Srivastava

abstract
The present investigation was carried out to study the population dynamics of important sucking insect’s pest of Okra viz., aphid, white fly and leaf hoppers and influence of various weather parameters on them at Vegetable research centre, Gobind Ballabh Pant University of Agriculture & Technology, Pantnagar, Uttarakhand, during 2016-2017. The incidence of aphid was recorded at 29th SMW (standard meteorological week) to 39 SMW, while whitefly at 30th to 39 SMW and hoppers at 30th to 39th SMW. The result revealed that peak incidence of aphid population was observed 29.70 aphids/3 leaves in 36th standard week followed by whitefly 12.13 whitefly/ 3 leaves in 37th SMW and leaves hoppers 11.13 hoppers/ 3 leaves. Correlation of aphid population with weather parameters shown non-significant positive correlation with maximum and minimum temperature(r = 0.527 and r = 0.096, respectively), wind velocity(r = 0.291) and relative humidity of morning (r = 0.149). However, rainfall (r = -0.612) and sun-shine hours (r = -0.309) indicated significant negative correlation while relative-humidity of evening (r = -0.397) showing non-significant negative correlation. In white fly there was non-significant positive correlation with maximum temperature (r = 0.460), wind velocity(r = 0.494) and relative humidity of morning (r = 0.117). Relative-humidity of evening (r = -0.624), rainfall (r = -0.655) and sun-shine hours (r = -0.625) showing significant negative correlation, but minimum temperature showing non-significant negative correlation. Hopper population correlated with weathers parameters indicated that there was non-significant positive correlation with maximum temperature (r = 0.513), relative humidity of morning (r = 0.153) and wind velocity (r =0.530) but have significant negative correlation with rainfall (r = -0.602) and sun-shine hours (r = -0.630) also non-significant negative correlation with minimum temperature (r = -0.291) and relative humidity of evening (r = -0.682*), respectively. The linear regression analysis using weather parameters as independent variables and aphid, white fly and hoppers as dependent variables could explain the variability up to 78% (R2= 0.78), 80% (R2 = 0.80) and 77% (R2 = 0.77), respectively.