Dissipation behavior, residue distribution and risk assessment of three fungicides in pears

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.

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.

The results provide a scientific basis for rationalizing the use of prochloraz, pyraclostrobin, and tebuconazole, and improving the safety of pears for eating. © 2019 Society of Chemical Industry.