Effect of intercropping and sowing dates on the incidence of pod borer, helicoverpa arnigera, yield and yield loss of chickpea

Abstract

Abstract : The study has been conducted at the Institute of Postgraduate Studies in Agriculture (IPSA), Gazipur, Bangladesh, during November, 1996 to March, 1997 to evaluate the effect of intercropping and the sowing dates on the incidence of chickpea pod borer as well as to estimate yield loss of chickpea due to pod borer. Pod borer infestation reduced the yield significantly and there existed a positive correlation (r= 0.994) between the level of pod borer infestation and yield loss. However, intercropping, in case of mid and late sowings, exhibited significant effect in reducing the pod borer infestation and yield loss in chickpea. On the other hand, the dates of sowing irrespective of the intercropping displayed a significant effect on pod borer infestation and yield loss. The early sowing resulted in significant reduction of pod borer infestation and yield loss. Pod borer infestation and yield loss were significantly higher in later dates of sowing. The highest yield was obtained from the plots of sole chickpea sown on November 18. Based on yield and gross return, it could be inferred that the sole chickpea should be sown by mid November. For late sowing, chickpea should preferably be intercropped with wheat to protect it against chickpea pod borer infestation.