title: Phototransformation of pesticides on plant leaves: the case of sulcotrione.
abstract: Photochemistry is one of the main ways of pollutants degradation in the environment. There is an obvious lack of data concerning the photostability of agrochemicals on plant foliage. We report here the first photodegradation study of a triketonic herbicide (sulcotrione) used as a substitute of atrazine. To mimic surface Leaves, we used films made of carnauba grey wax or of cuticular wax extracted from maize Leaves. Under simulated solar light, sulcotrione was rapidly phototyzed. The phototysis was much faster on cuticular wax films than in aqueous phase. Moreover, the formulated sulcotrione (Mikado) disappeared even more quickly than the pure active ingredient. Sulcotrione mainly underwent an intramolecular cyclization. To validate these observations, sulcotrione and its main photoproduct were monitored after maize field treatment. The day after the treatment the main photoproduct was detected on the maize leaves and suLcotrione had already significantly disappeared. This experiment demonstrates that phototysis can be a relevant process in real conditions after field treatment.
authors.affiliation: Laboratoire de Photochimie Moléculaire et Macromoléculaire, UMR CNRS 6505, FR-63177 Aubière Cedex, France.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Ter Halle
authors.forename: Jaroslaw
authors.initials: J
authors.lastname: Wiszniowski
authors.forename: Claire
authors.initials: C
authors.lastname: Richard
mesh_terms: D003512:Cyclohexanones / Q000737:chemistry*; D006540:Herbicides / Q000737:chemistry*; D008698:Mesylates / Q000737:chemistry*; D010573:Pesticide Residues / Q000032:analysis*; D010782:Photolysis; D018515:Plant Leaves / Q000737:chemistry* / Q000378:metabolism; D013997:Time Factors; D014867:Water / Q000378:metabolism; D014885:Waxes / Q000378:metabolism; D003313:Zea mays / Q000737:chemistry* / Q000378:metabolism
chemical_list: D003512:Cyclohexanones; D006540:Herbicides; D008698:Mesylates; D010573:Pesticide Residues; D014885:Waxes; D014867:Water; C079906:sulcotrione