The Residual Behavior Of Cyanothramide In Rice-Procambarus Clarkii Co-Culture System

The comprehensive rice planting model is a high-efficiency comprehensive cultivation mode in paddy field.Due to it's low toxicity and high efficiency,cyantraniliprole is one of the recommended pesticides for the control of Lepidoptera,Hemiptera and Coleoptera.However,there has been no study on the safe use of cyantraniliprole in the rice-Procambarus Clarkii co-culture system.In this experiment,a method for the determination of pesticide residues in the rice-Procambarus Clarkii co-culture system and paddy fields was established.The law of bioenrichment in Procambarus Clarkii and the influence on its body length,body weight and yield were studied.Results provide a scientific basis for the safe use of cyantraniliprole in the rice-Procambarus Clarkii co-culture system.The main research results are as follows:1.The method of detecting pesticides residue of cyantraniliprole in Procambarus Clarkii by LC-MS/MSIn this experiment,the residue analysis method of cyantraniliprole in tails,heads and all of Procambarus Clarkii was established.The detection limits(LODs)and limit of quantitation(LOQs)of the method were 0.513-0.725 ?g·kg-1 and 1.683-2.311 ?g·kg-1 in Procambarus Clarkii.The average recoveries of cyantraniliprole were 75.2-89.3%;the relative standard deviations were 2.64-10.15%,respectively.The extraction method determined by this experiment has good extraction efficiency;the purification method has better purification effect,and there is no impurity interference during the detection process;the detection method has good precision,sensitivity and accuracy.2.Comparison of residual dissipation dynamics of cyantraniliprole in the rice-Procambarus Clarkii co-culture system and paddy fieldsThe dissipation dynamics of cyantraniliprole showing a significant degradation trend,accorded with the first-order kinetic equation.At the 2 times of recommended dose,the dissipation curve R2 of cyantraniliprole in the rice-Procambarus Clarkii co-culture system and paddy fields of plants and waters were more than 0.69,half-life was 5.3 d,4.6 d and 4.6 d,5.3 d.After 42 days of application,the digestion rate of cyantraniliprole in plants and paddy waters has reached more than 99%.The residual dissipation dynamics of cyantraniliprole in soil showed a tendency of degradation after rise first.At 28 d,the residue of cyantraniliprole in the soil was relatively high.The final residue of cyantraniliprole in the rice-Procambarus Clarkii co-culture system and paddy fields of plants,rice,rice chaff and soil in one application were 0.013 mg·kg-1 and 0.011 mg·kg-11,<LOQ(0.515 ?g·kg-1),0.006 mg·kg-1 and 0.008 mg·kg-1.The final residue of cyantraniliprole is lower than its MRL value on cereal and brown rice(0.2 mg·kg-1).3.Bioenrichment of cyantraniliprole in Procambarus ClarkiiBioenrichment of cyantraniliprole in tails,heads and all of Procambarus Clarkii tend to reduce after the first rise.At the recommended dose and 2 times of recommended dose,cyantraniliprole in Procambarus Clarkii 0 to 14 d in the body over time and the increase of the content,at 14 d,the residue of cyantraniliprole in Procambarus Clarkii was relatively high,were 2.0-8.0 ?g·kg-1.After 60 days of application,the pesticide residue in tails,heads,and all of Procambarus Clarkii were lower than the LOQ value(0.513 ?g·kg-1).4.Effects of cyantraniliprole on the growth of Procambarus ClarkiiAccording to the growth and development of Procambarus Clarkii in CK field,one application at 45 g a.i./hm2,secondary application at 45 g a.i./hm2,one application at 90 g a.i./hm2 and secondary application at 90 g a.i./hm2,the body length and body weight were selected as the evaluation indexes.The average body length of Procambarus Clarkii were 7.83±0.67 cm,8.06±0.64 cm,7.81±0.61 cm,7.70±0.45 cm and 7.75±0.64 cm,respectively.The average body weight were 14.10±2.13 g,15.80±2.79 g,13.82±5.91 g,14.31 ±2.71 g and 13.55±3.49 g,respectively.The final yield were 86.3 kg/667 m2,88.1 kg/667 m2,81.0 kg/667 m2,86.0 kg/667 m2 and 86.6 kg/667 m2.Indicating that cyantraniliprole residue in the rice-Procambarus Clarkii co-culture system had no significant effect on the growth and development of Procambarus Clarkii.