Uptake, Translocation And Distribution Of The Fungicides Tricyclazole And Propiconazole In Rice Plants

Fusarium graminearum, which is the overriding pathogen of Fusarium head blight (FHB) Rice is an important food worldwide and especially in Asia. Rice blast, caused by the fungus Pyricularia oryzae, is the most destructive disease of rice. Although a variety of nonchemical methods for managing P. oryzae have been developed, including the use of disease-resistant varieties, biological control, and improved growing systems, fungicides are effective and easy to apply and are still widely used. The current study concerns the fate of the fungicides tricyclazole (TCZ) and propiconazole (PAZ) in rice plants after soil application. TCZ is a systemic, melanin biosynthesis-inhibiting fungicide that prevents the appressorial walls of P. oryzae from melanizing and that has a low risk of selecting for resistance in the field. PAZ is a protective and curative fungicide that inhibits demethylation and that is used to control a variety of plant diseases.In this study, the QuEChERS method was modified and used as to extract tricyclazole and propiconazole from leaf and root tissue of rice plants. A gas chromatography-mass spectrometer detection method of tricyclazole and propiconazole was established and used to measure the concentration of tricyclazole and propiconazole in plant samples.In a spike concentration range of0.1～10μg/ml, the recovery rates of tricyclazole and propiconazole in leaf sample were73%～109%and95%-104%; relative standard deviations (RSD) were3%7%and2%～9%respectively.; the recovery rates of tricyclazole and propiconazole in root sample were74%～98%and75%-87%; RSD were4%～11%and5%～8%repectively. The developed detection method is effective and easy to apply with high accuracy and precision and can be used for the analysis of pesticide residues in laboratory.Previous research has demonstrated that tricyclazole (TCZ) and propiconazole (PAZ) have good protective and curative activities against rice blast, a destructive and widespread fungal disease of rice. In this study, the uptake, translocation, and degradation of TCZ and PAZ in rice plants after soil application were investigated. A gas chromatography-mass spectrometry method was developed and used to determine the fungicide concentrations in the leaf and root tissue of rice plants as a function of time after soil treatment in a greenhouse experiment. In rice foliage, the mean foliar concentrations of TCZ and PAZ peaked at10days after soil application; the foliar concentrations then remained relatively stable or increased slightly until the end of the experiment (30days after application).21d after soil application, the concentrations of TCZ and PAZ in root samples gradually went down and then climb up to a second peak indicating that the concentrations of TCZ and PAZ show a double-peak pattern over time.In this study, a field trial was conducted to investigate the control effect of soil applied tricyclazole and propiconazole against rice blast. A10%soluble powder (SP) and30%suspension concentrate (SC) of tricyclazole and propiconazole was mixed at a rate of2:1and applied in field of Qianshan County, Anhui Province. The result indicates that the control effect of10%soluble powder of tricyclazole and propiconazole applied to soil at three levels1125a.i.g/ha,900a.i.g/ha and675a.i.g/ha were83.39±0.5%,78.38±10.01and63.80±1.34%respectively.10%tricyclazole-propiconazole SP has good control effect against rice blast especially at rate of1125a.i.g/ha and900a.i.g/ha. The control effects of30%SC applied at rates of301.5a.i.g/ha,225a.i.g/ha and148.5a.i.g/ha were83.73±3.01%,64.30±5.72%and64.44±6.22%respectively. Meanwhile, control effect of mixture of tricyclazole and propiconazole against other disease of rice for the further investigation and promotion.