Establishment of Pre-Harvest Residue Limit (PHRL) of Methoxyfenozide and Novaluron on Peaches

Abstract Methoxyfenozide and novaluron were sprayed with single and triple treatments separately on peachduring cultivation period. Samples were collected over 14 days, 8 times in total (0, 2, 4, 6, 8, 10, 12, 14 days).Methoxyfenozide and novaluron were extracted with acetone and partitioned with dichloromethane, and analyzed byHPLC/DAD. Method Quantitation Limit (MQL) were both 0.005 mg/kg, average recoveries of methoxyfenozide attwo fortification levels of 0.05 and 0.25 mg/kg were determined 92.7±2.9% and 102.8±3.1%, and novaluron were98.2±4.8% and 96.7±9.0%, respectively. The biological half-life of methoxyfenozide was about 4.41 days at singletreatment, and 4.24 days at triple treatments. The biological half-life of novaluron was about 14.81 days at singletreatment, and 14.50 days at triple treatments. Dissipation of pesticides on peach was influenced by growth dilutioneffect. In case of application of methoxyfenozide and novaluron following guidelines on safe use of pesticides, thefinal residue level was predicted to be lower than Maximum Residue Limit (MRL). Key words Biological half-life, Methoxyfenozide, Novaluron, Peach, Pre-Harvest Residue Limit (PHRL)