author(s)
Veer Vikram Singh, Neerja Agarwal, Sathish BN, Sanjeev Kumar, Sachin Kumar and Krishan Pal

abstract
A study on the insect diversity in mustard ecosystem was carried out in the field at Student Instructional Farm, C.S.A.U.A & T, Kanpur during winter of 2015-16. Altogether total four insect-pests Athalia lugens proxima (Klug), Bagrada cruciferanum (Burmeister), Chromatomyia horticola (Gourear) and Lipaphis erysimi (Kaltenbach) and four natural enemies, Coccinella septempunctata (Linnaeus), Coccinellla transversalis (Fabricius), Chrysoperla carnea (Stephens) and Xanthogramma scutellarae (F.) have been recorded. Among these pests, mustard aphid was found as key pest, which appeared on mustard crop at 51^st SW with a mean population of 2.25 aphids/10cm shoot/plant and reached its peak (225.5 aphids/10 cm shoot/plant) in the 8^th SW, whereas mustard saw fly appeared first from 51^st SW having 0.75 larvae/plant and reached to the peak (2.5 larvae/plant) at 2^nd SW. Among different predators C. septempunctata was observed as a most effective predator of aphid with predation ranging between 5 to 20 per cent in the field as per visual observation. As far as biotic factors of mustard aphid, L. erysimi were showed a high positive correlation with predators which indicate an important role of these natural enemies in suppressing the pest population to some extent.