Mustard is an important oilseed crop commodity contributing 28.3 and 19.8% in world acreage and production respectively (Kumar, 1999). Among various oil seed crops of india mustard occupies a predominant position contributing 23% of oilseed production(Vankatramani, 2000).Rape seed mustard is the second largest oilseed crop in the world providing 13% of the world's supply (Raymer et al., 2002). India occupies 7.00 million hectare area under rapeseed-mustard cultivation with average yield of 1.01 metric tons/ha (Anonymous, 2009). The mustard aphid, L. erysimi has gained the status of key pest of rapseed-mustard in India. Cultivation of resistant or tolerant varieties is the easiest way to protect mustard crop from insect pests.