Effect of Larval Density of Helicoverpa armigera (Hubner) on Pod Damage and Yield of Chickpea

Abstract

Background: Chickpea (Cicer arietinum L.) is cultivated in almost all parts of world covering more than 50 countries spread over Asia, Africa Europe, Australia, north America and South America countries and is the second most important food legumes crop after common bean (Phaseolus vulgaris L.). Chickpea has played a major role in realization of pulse Revolution in india making the country near self-sufficient in pluses. Gram is extensively grow in india. Due to its high nutritional value and its ability to fix atmospheric nitrogen, its more widely cultivated rabi pulse crop. The gram pod borer Helicoverpa armigera (Hubner) is most important pest of chickpea. Many pesticides were so far tested against this pest but due to over use of these pesticides resistance, residue and resurgence problems arises, beside destruction of natural enemies. Methods: To determination of per cent pod damage and yield of chickpea due to different larval density of H. armigera is an important tool to reduce the cost of cultivation by avoiding the unnecessary use of pesticides. Therefore, a pot experiment was conducted in arranged in a completed randomized design with four replications. The pots were placed under natural field conditions and take observation at Research farm, Rajasthan Agricultural Research Institute, Durgapura, Jaipur during 2015-16 and 2016-17. Result: The results revealed that least per cent pod damage (29.05, 24.78%) was recorded when the larval population was one per plant, while the maximum pod damage (64.55 and 67.76%) was recorded during 2015-16 and 2016-17, respectively. The simple liner correlation analysis indicated that there was a significant positive correlation (r= 0.989 and 0.999) between the larval density and per cent pod damage. Further, a significant correlation was noticed between larval density and number of healthy pods per plant, reduction in yield, yield per plant, total number of pod and damaged pods were -0.964, -0.976; 0.98, 0.986; -0.98, -0.986; 0.117, 0.126 and; 0.985 and 0.992, respectively during 2015-16 and 2016-17.