Residue decline and risk assessment of fluopyram + tebuconazole (400SC) in/on onion (Allium cepa)

Abstract

A method was validated for estimating fluopyram and tebuconazole in onion on LC-MS/MS using dispersive QuEChERS. Three sprays of a combination fungicide fluopyram + tebuconazole (Luna experience, 400 SC) were applied @ 75 + 75 and 150 + 150 g a.i. ha at an interval of 10 days on onion using Knapsack sprayer. First spray was made at bulb setting stage. Spring onion samples were drawn at 0 (1 h), 1, 3, 5, 7, 10, 15, and 20 days and matured onion bulb at harvest (52 days) after the last spray. Soil samples were also drawn at harvest. Foliar application of the combination product resulted in 1.14 and 2.86 mg kg fluopyram residues on spring onion at standard and double dose, respectively, one hour after the last application. The levels of fluopyram residues gradually declined and recorded 0.25 and 0.58 mg kg on 20th day of application with half-lives of 8.8 and 9.1 days at standard and double dose, respectively. For tebuconazole, the corresponding residues observed after 1 h (0 day) of application were 0.92 and 2.29 mg kg. The levels declined gradually to 0.12 and 0.33 mg kg on 20th days with half-life of 6.7 to 7.7 days at standard and double dose, respectively. Here, we are proposing a pre-harvest interval of 7 day for fluopyram and tebuconazole in spring onion when applied at 75 + 75 g a.i. ha (400 SC). Risk assessment was done by calculating hazard quotient and by comparing theoretical maximum residue intake (TMRI) with maximum permissible intake (MPI). In all the cases, results of the study showed that HQ (Hazard Quotient) ≤1 and TMDI < MPI. Hence, the use of this combination product can be recommended with pre harvest interval of 7 days. The data can be used in establishing MRLs (maximum residue limits) for spring onion after considering multilocation trials.

Persistence, dissipation kinetics, and waiting period of ethion on cucumber by gas chromatography‐electron capture detector

“…The impact of pesticide on human health, is not an easy and precise process because of differences in the periods and the levels of exposure, type of pesticide (with respect to toxicity), the geographic and meteorological characteristics of the agricultural areas where pesticides are applied etc [21,22]. Considering the human health risk due to pesticide toxicity and exposure, a greater risk is expected when the use of pesticides on food crops exceed maximum residue limit (MRL) which may leads to unwanted residues and constitute barriers to exporters and domestic consumptions.…”

Dissipation and residue determination of fluopyram and its metabolites in greenhouse crops

“…Up to date, fluopyram dissipation studies can be divided into those carried out in open fields and ingreenhouses. Open fields studies focus predominantly on the behaviour of the parent compound without taking into account the degradation compounds, 11,[16][17][18] although in one of them a single degradation compound was identified. 9 Also there is only one study conducted in greenhouse in which its degradation compounds were studied, 19 but the crop was in soil.…”

Dissipation of fluopyram and tebuconazole residues in/on pomegranate and soil in western maharashtra

“…According to Patel et al, 6 half life of fluopyram was 8.85 and 9.12days, respectively in recommended and double dose. Dong & Hu 15 showed half life of 6.48days for fluopyram in watermelon.…”

“…In chilli, Saha (2016) 5 found a half life of 1.161 and 1.241days for single (100g a.i./ha) and double (200g a.i./ha) application rate. For tebuconazole, half life of 6.69 and 7.72days was reported in onion 6 and 0.866 and 1.083 days in case of chilli 5 at the single and double dose, respectively. In other studies, the reported half life was 1.7 days Mohopatra et al 8 and 6days in onion Mohopatra et al 9 and mango 10 5.87 and 6.93 days in watermelon 15 4.49 days in ginseng, 11 1day in chilli 12 and 0.9days in tomato (Sing and Sing, 2014).…”