Effect of Different Colored Polythene Mulches and Net House on Insect Incidence and Yield of Brinjal in Rampur, Chitwan

Field experiment was conducted in single factor randomized complete block designed to evaluate effect of different color polythene mulch and net house on insect pest incidence of brinjal in chitwan, nepal during october 2016 to may 2017. Five different treatment were selected with four replications, included net house with black polythene mulch, black polythene mulch only, reflective polythene mulch only and black polythene mulch with emamectin benzoate 5%sg spray and control (no mulch+ no net + no pesticide spray)  . The result revealed that the net house totally restricts the brinjal shoot and fruit borer whereas black polythene mulch with emamectin benzoate spray plot reduced brinjal shoot and fruit borer larvae upto 70.58%. Total marketable yield was found highest in the black polythene mulch with emamectin benzoate spray plot (49.17 mt /ha) followed by black polythene mulch only (38.59 mt/ha) and lowest in control plot (28.53 mt/ha). Damaged fruit percentage by brinjal fruit and shoot borer was highest in the control (35.68%) followed by black polythene mulch (28.10%), reflective polythene mulch (19.02%) and lowest in net house with black polythene mulch (0%). The damaged weight inside the net house with black polythene mulch and black mulch with pesticide were significantly different whereas the damaged weight in other treatments similar which proved that there was no effect of mulch on brinjal shoot and fruit borer. The B:C ratio was the highest (3.34:1) in the black polythene mulch with emamectin benzoate spray plot while the lowest in net with black polythene mulch (1.68:1). Although the B:C ratio was lower in the net with black polythene mulch due to the low yield in the winter season. Creation of suitable soil environment by black polythene mulch and being biologically originated, having minimum residual effect and short half-life of emamectin benzoate, black polythene mulch with emamectin benzoate can be used for the eco-friendly management of brinjal shoot and fruit borer.