A non-destructive method for testing two components of the behaviour of soil-applied agricultural chemicals over a long period.

Marie-Anne Guglielmi, Françoise Rocher, Sandrine Legros, Jean-Louis Bonnemain, Jean-François Chollet

Index: Pest Manag. Sci. 68(6) , 897-905, (2012)

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Abstract

Owing to the complexity of soil composition, accurate predictions of both apoplastic systemicity of lipophilic xenobiotics and their leaching from the soil are made difficult. Therefore, a non-destructive method to assess directly these two components of the spatial behaviour of soil-applied phytochemicals is needed.The plant selected was a dwarf tomato, which can exude an abundant apoplastic fluid through large stomata for several months. The feasibility and reliability of the method were assayed using three triazoles exhibiting different log D values. HPLC-MS analyses indicated that triadimenol (log D = 2.97) was clearly the most mobile compound within the apoplast, especially its diastereoisomer A. Propiconazole (log D = 3.65) and penconazole (log D = 4.64) exhibited a similar low systemicity. The data remained the same when the three fungicides were applied together on the soil. Long time-course studies (1.5 months) of penconazole behaviour indicated that, in contrast to leaching, which decrease sharply, root-to-shoot translocation remained almost unchanged during the whole experiment, in spite of the high lipophilicity of this fungicide.This method must contribute to a better knowledge of the behaviour of commercial soil-applied phytochemicals. It can also be used to screen new xenobiotics within strategies to satisfy environmental requirements.Copyright © 2011 Society of Chemical Industry.