Population Dynamics of Helicoverpa armigera Hubner (Noctuidae: Lepidoptera) in Tomato

The fruit borer, Helicoverpa armigera Hubner (Noctuidae: Lepidoptera) was first recorded in the last week of February. The peak activity of the pest was observed during first week of April (6.65 per plant). Correlation between various abiotic factors viz., maximum temperature, sunshine, rain fall, evening relative humidity and wind speed and H. armigera larval population were found to be non significant. However, minimum temperature and evaporation exhibited significant positive correlation (r = 0.85 and r = 0.90, respectively) with H. armigera larval population. It can be said that with every unit increase in minimum temperature and evaporation, there was an increase in H. armigera larval population to the tune of 2.9 and 0.8 larvae per plant respectively. Further, significant negative correlation (r = - 0.81) was observed between morning relative humidity and H. armigera larval population.