Influence of Abiotic Factors on Trap Catch of Gram Pod Borer, Helicoverpa armigera (Hubner) in Redgram, Cajanus cajan (L.) Millsp. Ecosystem

Abstract

An experiment was conducted to study the influence of weather parameters on trap catches of Helicoverpa armigera (Hubner) in redgram Cajanus cajan (L.) ecosystem during kharif 2017 at experimental farm of NPRC, Vamban and farmer’s field at Vadakaddu with green colour funnel pheromone traps containing Heli lure. The highest catch (98 moths/ 5 traps) was recorded on January 2nd SMW at Vamban and on 52nd SMW of December at Vadakaddu. In both the locations lowest catch of 20 moths/ 5 traps and 30 moths/ 5 traps were recorded on 35th SMW. The moth catches had highly significant negative correlation with maximum temperature (r = -0.79**), (r = -0.79**), minimum temperature (r = -0.66**), (r = -0.68**), wind speed (r = -0.71**), (r = -0.73**), rainfall (r = -0.54**), (r = -0.51**), rainy days (r = - 0.54**), (r = -0.52**) and sunshine hours (r = - 0.44**), (r = -0.42**) at Vamban and Vadakaddu, respectively. But there was highly significant positive correlation with relative humidity (r = 0.78**) and (r = 0.76**) at Vamban and Vadakaddu, respectively. The regression analysis resulted with an R2 value of 0.791, which indicates that 79.1% catches depends on all the weather parameters at Vamban and R2 value of 0.829 indicating that 82.9% of catches depends on all the weather parameters at Vadakaddu.