Vol. 11, Special Issue 1 (2022)

Author(s):
Amar Chand, SK Khinchi, KC Kumawat, Akhter Hussain and SL Sharma

Abstract:
The field experiment was conducted during Rabi, 2019-20 and Rabi, 2020-21. The population of mustard aphid, L. erysimi first appeared in the last week of December (52^nd Standard Meteorological Week) and increased gradually week after week and attained to its peak in second week of February (6^th SMW) during both the years. The peak activity of aphid was observed at 26.50- 23.3 ⁰C maximum, 4.90-5.30 ⁰C minimum temperature and relative humidity 55.0-57.0 per cent during the two consecutive years (Rabi, 2019-20 and Rabi, 2020-21). After the peak population, the population of aphid started to decline and reached to low level in the 9^th SMW near maturity of the crop during both the years. The maximum temperature had significant negative correlation and minimum temperature had non significant negative correlation, whereas, relative humidity had non-significant positive effect with aphid population during both the years Rabi, 2019-20 and Rabi, 2020-21. The occurrence of natural enemies ladybird beetle, C. septempunctata and syrphid fly, X. scutellarae with the population of aphids during both the years and the enemies viz., C. septempunctata and X. scutellarae had significant positive correlation with the population of mustard aphid and population of C. septempunctata had non-significant negative correlation with maximum and minimum temperatures while, non-significant positive correlation with relative humidity during both the years Rabi, 2019-20 and Rabi, 2020-21.