title: Effect of two formulations on the decline curves and residue levels of rotenone in cabbage and soil under field conditions.
abstract: The dissipation and residue levels of rotenone with suspension concentrate (SC) as well as water dispersible granule (WDG) formulations in cabbage and soil were investigated under field conditions. The decline curves of rotenone residues in cabbage and soil corresponded with first-order kinetics. The dissipation rate of rotenone in cabbage was faster than that in soil. The half-lives of the SC formulations in cabbage and soil were 1.14d to 1.85d and 2.26d to 3.98d, respectively. For the WDG formulation, the values were 1.33d to 1.96d and 2.41d to 3.38d. Less spraying, lower dosage, and longer pre-harvest intervals could reduce terminal residue levels. Terminal residues below the MRL (0.5mg kg(-1)) were achieved after pre-harvest intervals of 3d at either once (45g a.i. ha(-1)) or twice (90g a.i. ha(-1)) the recommended dosage. The different dissipation processes of rotenone in cabbage and soil under field conditions could be attributed to the different climate and soil properties, and the types of formulation had no apparent effect on half-life. Formulation type affected the initial concentrations and finally led to different terminal residues. Prolonged pre-harvest intervals are necessary to ensure that the products are sufficiently safe for consumption.
authors.affiliation: Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, PR China.
authors.forename: You
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, PR China.
authors.forename: Kun
authors.initials: K
authors.lastname: Wang
authors.affiliation: Environment and Plant Protection Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, PR China.
authors.forename: Chao
authors.initials: C
authors.lastname: Yan
authors.affiliation: Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, PR China.
authors.forename: Wei-Sheng
authors.initials: WS
authors.lastname: Li
authors.affiliation: Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, PR China.
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.affiliation: Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, PR China.
authors.forename: Ning
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, PR China. Electronic address: zdsys@scau.edu.cn.
authors.forename: Zhi-Xiang
authors.initials: ZX
authors.lastname: Zhang
mesh_terms: D001937:Brassica / Q000737:chemistry*; D002980:Climate; D004784:Environmental Monitoring; D006207:Half-Life; D010573:Pesticide Residues / Q000032:analysis*; D012402:Rotenone / Q000032:analysis*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D010573:Pesticide Residues; D012987:Soil; D012989:Soil Pollutants; D012402:Rotenone
keywords: Biopesticide; Dissipation; Formulation; Residue; Rotenone