Preservative Effects of Strobilurin Fungicides on Citrus Storage Diseases and Residue Safety Assessment

Ethofenprox, pyraclostrobine, trifloxystrobin and enestroburin are strobilurin fungicides that can effectively control fungal diseases caused by ascomycetes, zygomycetes, imperfect fungi, etc. With the purpose of guaranteeing the safe use of strobilurin fungicides in the prevention and treatment of citrus diseases, toxicity and control effects of the fungicides on citrus storage diseases and GC-MS (gas chromatography-mass spectrometry) were applied in this study to determine its residual safety. The results indicated that ethofenprox, trifloxystrobin, pyraclostrobine, and enestroburin had excellent inhibitory effects on citrus storage diseases at concentration of 200-400 ug/mL. Degradation dynamics of 4 fungicides during the storage period of citrus could be expressed as the first-order kinetics equation. The fungicides could penetrate into flesh through peels slowly. Therefore, the residue content of the fungicide on peels was higher than that in the flesh of the same citrus. After citrus fruits were treated for 90 d, the residues were lower than the maximum residue limits in all the countries, so the citrus were safe. This investigation provided the theoretical guidance and technical support for the quality evaluation of citrus products.