Effect of abiotic factors and date of sowing on population dynamics of Helicoverpa armigera (Hübner) on Chickpea

Studies on the effects of date of sowing and weather variables on population dynamics of Helicoverpa armigera attacking chickpea crop in Haryana, India conducted at CCS Haryana Agricultural University, Hisar during 2015-16 and 2016-17. Population dynamicsof H. armigera in chickpea variety HC 1 was studied on four dates of sowing i.e. 15th October (D1), 30th October (D2), 15th November (D3), and 30th November (D4) during both years. Larval population of H. armigera commenced at 5th SMW in all sowings. Maximumlarval population of H. armigera was observed in the 12th SMW of the fourth date of sowing (7.59 l/mrl) whereas it was minimum (0.13 l/mrl) in the 5th SMW of the third date of sowing, indicated that sowing had a significant effect on the population of H. armigera.The larval population of H. armigera was comparatively higher in late sown crops (15th and 30th November) than in early sown crops (15th and 30th October). The correlation of the larval population of H. armigera with weather variables indicated a significant andpositive correlation with sunshine hours (r= 0.77**, r= 0.76**) during the first and second dates of sowing. However, on the third date of sowing it showed a significant and positive correlation with maximum temperature, minimum temperature, and sunshine hours. Similarly on the fourth date of sowing larval population of H. armigera showed a positive and significant correlation (r= 0.85** and 0.82**) with maximum and minimum temperature while the correlation was significant and negative (r= -0.75*) with evening relative humidity. The larval population of H. armigera exhibited a significant and positive correlation with temperature and sunshine hours during both years.