Methamidophos (MAP) was banned in China since 2004 due to high toxicity, but was successfully replaced by acephate (ACE), a low toxic organophosporous insecticide. No or less studies had explored ACE/MAP residues in pear fruits. The present study aimed to explore the transfer of ACE and its transformation to MAP in pear fruits (from Dangshan crisp pear), after ACE was administered by three different methods. It also aimed to evaluate the risk of ACE residues in pear fruits. Three different methods of ACE administration used in the study included the following: broadcast, spraying after bagging fruits, and root irrigation. The residual insecticide in pear fruits at various time points till 35 days after ACE administration was detected by an ultra-high performance liquid chromatography-tandem mass spectrometric method. The results showed that the broadcast spraying method directly resulted in ACE deposits on pear fruits. ACE could transfer to fruits through leaf and roots. Regardless of administration methods, ACE and its metabolite MAP were identified in pear fruits. ACE residues after 21 d of spraying were lower than the required limit in fruits byChina. Among the three methods, the spray after bagging fruits effectively avoided the direct contact of fruits with ACE, and hence reduced the amount of insecticide residues in fruits to a greater extent. This method is effective to improve the quality and safety of pear fruits.

Transport and transformation of acephate and its metabolite methamidophosin in pear trees

248th National Meeting (2014)

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