Metabolism of the Strobilurin Fungicide Mandestrobin in Wheat
2018
Ando, Daisuke | Fujisawa, Takuo | Katagi, Toshiyuki
The metabolic fate of a new fungicide, mandestrobin, labeled with ¹⁴C at the phenoxy or benzyl ring was examined in wheat after a single spray application at 300 g/ha. Mandestrobin penetrated into foliage over time, with both radiolabels showing similar ¹⁴C distribution in wheat, and 2.8–3.3% of the total radioactive residue remained on the surface of straw at the final harvest. In foliage, mandestrobin primarily underwent mono-oxidation at the phenoxy ring to produce 4-hydroxy or 2-/5-hydroxymethyl derivatives, followed by their subsequent formation of malonylglucose conjugates. In grain, the cleavage of its benzyl phenyl ether bond was the major metabolic reaction, releasing the corresponding alcohol derivative, while the counterpart 2,5-dimethylphenol was not detected. The constant RS enantiomeric ratio of mandestrobin showed its enantioselective metabolism to be unlikely on/in wheat.
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