Int.J.Curr.Microbiol.App.Sci (2020) 9(7): 2785-2790 2785 Original Research Article https://doi.org/10.20546/ijcmas.2020.907.328 Insect Pests of Mustard and their Natural Enemies in Assam P. P. Pradhan*, R. N. Borkakati and D. K. Saikia AICRP on Biological Control, AAU, Jorhat Centre , Department of Entomology, Assam Agricultural University, Jorhat-785 013, India *Corresponding author ABSTRACT Introduction Oilseed crops play a vital role in Indian agricultural economy. Mustard, Brassica juncea L. is one of the first domesticated oilseed crops amongst all the plants under family Cruciferae. Rapeseed &mustard (Brassica spp.) is cultivated throughout India in spite of diverse agro-climatic conditions ranging from north-eastern/north-western hills to down south under irrigated/rainfed, timely/late sown, saline soils and mixed cropping over an area of 5.96 million hectare with a production of 8.32 million tones and productivity of 1397 kg/ha in 2017-18 in India. Assam records 0.29 million hectare of area with an annual production of 0.19 million tonnes which gives an annual yield about 669 kg/ha (Anonymous, 2018). Among the various factors responsible for the low yield of mustard, damage inflicted by various insect pests is an important factor. Study of different insect pests are very essential to develop future transgenic plant of cruciferous vegetable (Shelton et al., 2009). Rai, 1976 enlisted a total of 24 species of key insect pests of mustard and rapeseed crop in India which responsible for severe infestation in different stages of crop. Further, Purwar et al., 2004 recorded more than 43 species of insect pests of rapeseed-mustard crop in India, International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 9 Number 7 (2020) Journal homepage: http://www.ijcmas.com Field experiment was conducted in Instructional-Cum-Research (ICR) farm, Assam Agricultural University, Jorhat during rabi 2018& 2019 to investigate the insect pests and natural enemies of mustard. During the period of present investigation, a total number of four insect pests from four different families viz, mustard aphid, Lipaphis erysimi (Kalt.); mustard sawfly, Athalialugens proxima (Klug); Flea beetle, Phyllotreta Cruciferae (Goeze); cabbage butterfly, Pieris brassicae (Linn.) were recorded at different stages of mustard crop. On the other hand, total three predators viz, coccinellid beetle (Coccinella transversalis (Fab.) and Harmonia axyridis (Fab.), green lacewing, Chrysoperla carnea (Stephens); syrphid fly, Xanthogrammas cutellaris (Fab.) and one aphid parasitoid, Diaeretiella rapae (M’lntosh) were recorded as major natural enemies on insect pests of mustard. However, out of both coccinellids C. transversalis was dominant and considered as major predator of aphids. Keywords Mustard, Insect pests, Natural enemies, Predator, Coccinellids Accepted: 22 June 2020 Available Online: 10 July 2020 Article Info