Effect of Pest Exclusion Net (PEN) on the Sustainable Production of Late Season Broad Leaf Mustard (BLM) in Chitwan, Nepal

Broad leaf mustard (BLM) (Brassica juncea L. var. rugosa, Brassicaceae) is one of the most widely consumed vegetable crops in Nepal. The production of crop in open field is constrained by major pests like mustard aphid and flea beetle. This study was aimed to determine the effects of pest exclusion net (PEN) on pest-infestation and yield of BLM cultivar “Khumal Broad Leaf”. The experiment was carried out in randomized complete block design (RCBD) with five treatments and four replications. The treatments included control (no mulch + no net + no pesticide spray), black plastic mulch only, reflective plastic mulch only, black plastic mulch + no net + pesticide spray, and PEN + black plastic mulch + no pesticide spray. Data were analyzed with RSTAT software package and means were separated by Duncan’s multiple range test (DMRT) at 5% level of significance. The result revealed that crop under PEN had highest plant height (38.99 cm), lowest number of aphid (0-0.86 per plant), flea beetle (0-1.07 per plant) and highest total marketable yield (77.50 ton/ha) while control had lowest plant height (20.06 cm), highest number of aphid (maximum 2.49 per plant), flea beetle (maximum 2.00 per plant) and lowest total marketable yield (13.75 ton/ha). Economic analysis revealed highest benefit-cost ratio in PEN (9.90). This study indicates that the use of PEN protect BLM against aphid and flea beetle, increases yield and can be considered as a viable technology for BLM production by smallholder growers of Nepal.