author(s)
SR Padaliya, RK Thumar, MD Aniyaliya and BG Timbadiya

abstract
A study on population dynamics of thrips, Scirtothrips dorsalis Hood on Bt cotton was conducted at Anand Agricultural University, Anand during Kharif 2017-18. The incidence of the pest started from last week of July to end of crop season with peak activity in 2^nd week of December. The higher activity of this pest was noticed during November and December (8.24 to 14.24 thrips/leaf). The correlation coefficient data indicated that rainfall (r=-0.54**), wind speed (r=-0.61**), minimum temperature (r=-0.92**), morning relative humidity (r=-0.67**), evening relative humidity (r=-0.84**), morning vapour pressure (r=-0.92**) and evening vapour pressure (r=-0.82**) were highly significant negatively correlated with thrips population. The bright sunshine hour(r=0.57**) and evening vapour pressure deficit (r=0.65**) had highly significant positive correlated with the activity of thrips.