ABSTRACT A field experiment was conducted during Rabi 2019-2020 at Research Farm of Agricultural Research Sub Station Nagaur (Agriculture University, Jodhpur) to know the pest incidence in mustard variety ‘BIO 902’. The incidence of aphid 3.65 aphids per plant started in the first week of January (1st SMW) continued thereafter for a long period and reached to maximum 128.80 aphids per plant in the third week of February (7th SMW). The incidence of ladybird beetles appeared in the second week of January and reached its peak 9.95 coccinellids/plant in the third week of February (7th SMW). The correlation coefficient of L. erysimi with ladybird beetle population had a positive significant correlation (r= 0.979).

Keywords: Mustard aphid, Lipaphis erysimi, population dynamics, biotic factors, ladybird beetles, coccinellids