BACKGROUND: Fungicides are often applied to pears before they are kept in storage facilities. The scientific application of pesticides can reduce unnecessary exposure, which in turn could benefit both humans and the environment. RESULTS: We investigated dissipation behavior and residue distribution, and conducted risk assessments for prochloraz, pyraclostrobin, and tebuconazole in pears stored under different conditions using ultra-performance liquid chromatography (UPLC). The recoveries of the three fungicides ranged from 76.5% to 114.5%, and the coefficients of variation were 1.0%-8.5%. The half-life (t 1/2 ) ranges for degradation of the three fungicides in Dangshan Su pear peel were 8.8-13.9 days after storage at 25°C and 99.0-346.6 days after storage at 2°C. Among the three fungicides, tebuconazole had the lowest residue concentration in pear pulp (maximum of 0.226 mg·kg −1 ) and the longest half-life (≥ 231.0 days). Accordingly, among these fungicides, tebuconazole is the most suitable for the preservation of Dangshan Su pears during storage. Finally, we analyzed samples of six pear varieties from markets in China and found that the residue concentrations of the three fungicides in pear pulp and fruit met Chinese standards.CONCLUSION: The results provide a scientific basis for rationalizing the use of prochloraz, pyraclostrobin, and tebuconazole, and improving the safety of pears for eating.

BACKGROUND: Cyantraniliprole, a second-generation diamide insecticide, was recently introduced in China, where the rice-crayfish integrated system (RCIS) is practiced to control rice pest infestations. The aim of this study was to investigate the residue behavior of cyantraniliprole in RCIS and its potential ecological effects on nontarget Procambarus clarkii in order to recommend safe pesticide application strategies.RESULTS: Cyantraniliprole dissipated in rice plants according to first-order kinetics, with an average half-life of 5.25 days and a dissipation rate of >95% over 28 days. The terminal cyantraniliprole residue levels in rice straw, paddy hull and brown rice were all within 0.2 mg kg −1 , which is the China-recommended maximum residue limit. The tissues of P. clarkii accumulated and distributed cyantraniliprole in the descending order gill > hepatopancreas > intestine > muscles. Procambarus clarkii exposed to cyantraniliprole exhibited a moderate decrease in weight gain, specific growth rate and condition factor compared to the control group. Exposure of P. clarkii to cyantraniliprole caused histopathological alterations to the hepatopancreas, but the alterations were not statistically significant in the 60 g ai ha −1 cyantraniliprole group when compared with the control group.CONCLUSION: We suggest that 10% cyantraniliprole oil dispersion be sprayed twice at an interval of 14 days and dosage of 60 g ai ha −1 during the growth stage of rice in RCIS.

Prochloraz is a fungicide that is widely used on vegetables to maintain freshness during storage. To ensure that prochloraz is used in a safe way that reduces the levels of residue on the product, we evaluated two treatment methods (soaking and spraying) that are commonly used for garlic sprouts. An ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for prochloraz residue on garlic sprouts. The linear range of the method was 5–500 μg/kg and the correlation coefficient was 0.9983. The average recovery range was 88–94%, and the relative standard deviation range was 2.6–9.7%. Garlic sprout samples that had been soaked in or sprayed with prochloraz were collected from cold storage facilities in Laixi and Pingdu, China. For the soaked samples, the ranges for the levels of prochloraz residue on the whole garlic sprouts and stems (edible portion) were 15.76–25.14 mg/kg and 0.58–1.62 mg/kg, respectively. For the sprayed samples, the ranges for the levels of prochloraz residue on the whole garlic sprouts and stems were 1.85–7.89 mg/kg and 0.01–1.29 mg/kg, respectively. The results of this study provide a scientific basis for rationalizing the use of prochloraz and improving the safety of edible garlic sprouts.