Effect of Nitrogen, Phosphorus and Potash on Mustard Aphid and Yield Attributing Characters of Mustard in Cold Arid Region (Ladakh)

Field experiments were conducted at Regional Agricultural Research Station, Leh (Ladakh) during kharif 2004–05 and 2005–06 to evaluate effect of nitrogen, phosphorus, potash on aphid population and yield parameters of mustard. The experiment was laid out in a randomized block design with 10 treatments of different fertilizer dosages i.e. N (20, 40, 60 and 120 kgha⁻¹) and P (0, 20 and 40 kgha⁻¹) and K (0, 20 and 40 kgha⁻¹). It was found that application of only nitrogen or higher dosage of nitrogen increased the aphid population while application of phosphorus and potash with or without combination of nitrogen reduced the population build up. However, application of 120 kgha⁻¹ nitrogen increased the yield despite higher population.