Effect of weather parameters on incidence of key pest, Helicoverpa armigera (Hubner) on tomato

Abstract

A field experiment was conducted at Central Research Farm, SHIATS, Naini, Allahabad during Rabi, 2014-15 to study the effect of weather parameters on incidence of Helicoverpa armigera (Hubner) on tomato during Rabi, 2014-15. The incidence of H. armigera started in 8th standard meteorological week (third week of February) with an average population of 2.0 larvae per plant thereafter, larval population increased gradually and reached to its peak level (6.0 larvae per plant) in 12th standard meteorological week (third week of March). Weather parameters, temperature [maximum (r = 0.625) and minimum (r = 0.668)], wind velocity (r=0.527) and sunshine hours (r=0.722) showed significant positive correlation with larval population. Relative humidity [morning (r=-0.160) and evening (r=-0.388)] had non-significant negative correlation while, rainfall had non-significant positive correlation (r=0.091) with larval population.