Alterations in Soil Enzyme Activities in Response to New Generation Diamides

Impact of diamides on structure and functional activities of soil microflora and soil health has not been well studied. Effect of chlorantraniliprole and cyantraniliprole on the activity of dehydrogenase, acidic, alkaline phosphatase, amylase, invertase and urease enzymes in chilli planted soil was assessed. Two applications of chlorantraniliprole @ 30, 37.5 and 60 g a.i. ha⁻¹ and cyantraniliprole @ 60, 75 and 120 g a.i. ha⁻¹resulted in adverse effect. Dehydrogenase activity was reduced by 21.34 and 22.07 per cent on 7^thday, in double dose chlorantraniliprole and cyantraniliprole respectively. Activity of both acidic and alkaline phosphatase enzyme reduced by 4.98 and1.06 per cent at 5th day after application of chlorantraniliprole and cyantraniliprole @30 and 60 g a.i. ha⁻¹ respectively. On the other hand, amylase and invertase activity showed non-significant reduction and urease enzyme activity was slightly reduced (0.02–3.44%). The recommended doses of these two diamides had short term adverse effect on these enzymes, while higher doses led to 20 -30 per cent reduction in enzyme activity). However, activity of enzymes was restored after some time which could be due to adaptive capacity of soil microbes and dissipation of the pesticide residues.