Dissipation pattern and risk assessment of flubendiamide on chili at different agro-climatic conditions in India

Dissipation kinetics and dietary risk assessment of spiromesifen on major summer vegetables using good agricultural practices

Dissipation kinetics and dietary risk assessment of spiromesifen is worked out on four summer vegetables, viz. okra, chilli, capsicum and brinjal (eggplant or aubergine) during March-April 2015 at the experimental farm of the Department of Entomology, Dr. Yashwant Singh Parmar University of Horticulture and Forestry Nauni, Solan using good agricultutral practices. Two foliar applications of spiromesifen @ 144.0 g.a.i./ha each were given at 10 days interval with a knapsack sprayer with the first application at the fruit initiation stage. Sample were collected up to 15 days after pesticide application and processed using a modified QuEChERS method, which was validated by doing recovery studies having recovery range and RSD within established guidelines of SANCO. Estimation of spiromesifen residues was conducted on GC-MS. The initial deposits after spraying of spiromesifen on okra, capsicum, chilli and brinjal fruit after 2 h of treatment were 1.327, 0.727, 0.800 and 0.738 mg/kg, respectively. The residues persisted up to 7 days and further dissipated and declined below the limit of quantification of <0.025 mg/kg at 10 days after treatment in all of the crops under investigation. Dissipation of spiromesifen followed first-order kinetics. The spiromesifen residues dissipated to half in 1.6, 1.8, 1.9 and 1.7 days with the suggested safe waiting period of 8.9, 5.2, 6.0 and 7.0 in the respective crops. The hazard quotient was <1 and theoretical maximum dietary intake was less than the maximum permissible intake, which was less than the maximum residue limit in all of the vegetable crops under investigation.

A monoclonal antibody-based indirect competitive enzyme-linked immunosorbent assay for flubendiamide detection

Flubendiamide (FD), the first commercial phthalic acid diamide that targets insect ryanodine receptor (RyRs), has played an important role in pest management. With its extensive worldwide application, a rapid and convenient method to detect its existence in the environment is necessary. In this study, an indirect competitive enzyme-linked immunosorbent assay (icELISA) was developed to analyse FD residue on environmental and food samples. The established icELISA showed a half maximal inhibition concentration (IC₅₀) of 17.25 µg L^-1, with a working range of 4.06-103.59 µg L^-1 for FD, and showed no cross-reactivity with chlorantraniliprole, cyantraniliprole, and several FD analogues. Average FD recoveries from spinach, tap water, and soil samples were 89.3-112.3%, 93.0-102.1%, and 86.9-97.6%, respectively. Meanwhile, FD detection results of icELISA were compared with those of ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The comparable results verified that icELISA was suitable for rapid detection of FD residue in environmental and agricultural samples.

Dissipation kinetics of spinosad from tomato under sub-tropical agro-climatic conditions

The dissipation of spinosad in/on tomato and soil was studied at Indian Agricultural Research Institute, New Delhi, under field condition. The optimized sample preparation technique using high performance liquid chromatography (HPLC) with UV detector gave the limit of quantification (LOQ) of 0.05 μg g(-1) of tomato. Spinosad residues were below the determination limit in/on tomato fruits after 15 days of application for recommended dose (51 g a.i. ha(-1)). The half-life of spinosad was in between 3.18 to 3.74 days for the recommended dose. Similarly half-life of 4.14 to 4.71 days was observed for double the recommended dose. The study also investigated the persistence of spinosad in soil and it has been found that half-life of spinosad in soil was 5.49 to 6.36 days for the recommended dose and 6.76 to 6.91 days for double the recommended dose. Based on the CODEX-MRL of spinosad (0.3 mg kg(-1)), pre-harvest interval (PHI) was 7.54 days for the recommended dose of spray.