Effect of Sowing Dates on the Seasonal Abundance of Mustard Aphid [L. erysimi (Kalt)] and Associated Natural Enemies in Vidarbha, Maharashtra, India

Present study on effect of sowing dates on the seasonal abundance of mustard aphid (L. erysimi (Kalt) and natural enemies associated with mustard aphid in Vidarbha region (Maharashtra) along with correlation with weather parameters was carried at the field of AICRP on Linseed and Mustard, Nagpur (Dr. PDKV, Akola) during Rabi 2024-25. Seasonal incidence of mustard aphid was recorded on mustard crop sown on 19th October 2024 (In first week of optimum sowing period recommended by the university), 9th November 2024 (In last week of optimum sowing period recommended by the university), and 6th December 2024 (Late sown condition recommended by the university). The crop sown on 19 October revealed a highest peak of 101.1 aphids/10 cm shoot during the 3rd SMW, a lowest peak of 14.2 aphids/10 cm shoot during 4th SMW for the second sowing date (09 November) and a moderate peak of 57.9 aphids/10 cm shoot was evident for sowing on 06 December during 5th SMW. For the crop sown in the first week of optimum sowing period, morning relative humidity showed a significantly positive (0.540*) correlation with aphid population, while other weather parameters were non-significant. For the crop sown in the last week of optimum sowing period all the weather parameters had non-significant correlations with aphid abundance. Under late sown condition, maximum and minimum temperatures showed significantly negative (-0.526*/-0.566**) correlation with aphid population, while, other weather parameters exerted non-significant effect. For the crop sown in the first week of optimum sowing period and last week of optimum sowing period, both natural enemies registered non-significant correlations with all-weather parameters, whereas, for the crop sown under late sown condition, both the natural enemies, ladybird beetle and D. rapae abundance was significantly correlated negative (-0.545*/0.678**) and negative (-0.644*/-0.642**) with maximum and minimum temperatures, respectively. The population of the aphid predator, the ladybird beetle, was significantly and positively correlated with the aphid population for all three sowing dates (0.653*/0.940*/0.816**). In contrast, the correlation of D. rapae with the aphid population was non-significant and negative (-0.018) during the first sowing date, but showed a significant positive correlation during the second and third sowing dates (0.789**/0.770**).