Monitoring of gram pod borer, Helicoverpa armigera (Hübner) through pheromone traps on long duration pigeonpea [Cajanus cajan (L.) Millsp.]

Abstract

The population of H. armigera was monitored using pheromone traps installed in the pigeonpea (cv. Bahar) fields at Varanasi during Kharif season of the year 2015-16 and 2016-17. During both the years, the adult male moth activities were first noticed in the 4th standard week and the population attained its peak level in the 12th standard week (7.5 moths/ trap and 10 moths/ trap, respectively). The correlation between pheromone trap catches and larval count for same week were highly significant and positive, r = + 0.952** and r = + 0.904**. Correlation analysis with weather parameters indicated that the emergence of H. armigera adults had a significant positive association with maximum temperature, minimum temperature and sunshine hours, while relative humidity exhibited a significant negative correlation with adult moth activity. The regression equation revealed that variations of different weather variables caused approximately 88.8 and 85.6 per cent variations in H. armigera trap catches during both years, respectively.