Residual dynamics of azoxystrobin and combination formulation of trifloxystrobin 25% + tebuconazole 50%-75 W G on isabgol (Plantago ovata Forssk.) and soil

Abstract

To elucidate the fate of azoxystrobin and combination formulation of trifloxystrobin and tebuconazole in isabgol ecosystem, a simple and efficient analytical method was developed using QuEChERS (quick, easy, cheap, effective, rugged and safe) extraction method followed by analysis in gas chromatography combined with electron capture and nitrogen-phosphorus detector. The method gave very good overall mean recoveries in the range of 69–91%. The limit of quantification were 65, 25, 40 μg kg−1 for azoxystrobin, trifloxystrobin and tebuconazole in isabgol herbage, respectively. The values for corresponding fungicide in soil were 50, 25 and 25 μg kg−1, for isabgol seed with husk were 80, 50 and 75 μg kg−1, respectively. The results revealed that the dissipation pattern of studied fungicides in the soil and isabgol herbage followed first-order kinetics. The half-life of trifloxystrobin in isabgol herbage were shorter (3.0–3.3 days) than tebuconazole (5.1–5.6 days) and azoxystrobin (5.5–7.7 days). Similarly soil half-lives were also shorter for trifloxystrobin (5.0–6.1 days) as compared to tebuconazole (7.9–8.6 days) and azoxystrobin (8.4–10.0 days). The residues of these fungicides in soil, isabgol herbage and seed with husk at harvest were below the detectable limit which supports the application of these fungicides in the management of fungal diseases in isabgol.