Absorption, Translocation and Metabolism of the Fungicide Triflumizole in Cucumber Plants

Abstract

Absorption, translocation and metabolism of an imidazole fungicide triflumizole, (E)-4-chloro-a,a,a-trifluoro-iV-(l-imidazol-l-yl-2-propoxyethylidene)-0-toluidine were studied in cucumber plants after leaves and fruits had been treated with [phenyl-U-14C] triflumizole. The symplastic movement of triflumizole from the treated leaf to untreated plant parts including fruit was negligibly small. Triflumizole was rapidly decomposed with a half-life of ca. 4 days. Autoradiography and bioassay showed that triflumizole was translocated apoplastically into the treated leaf and reached the concentration enough to control powdery mildew. Dissipation of 14C was slower in the treated fruit than in the treated leaf because of faster and larger absorption of 14C into the peel and flesh. The half-life of triflumizole in the treated fruit was 6 days. The concentration of total residual 14C in the fruit was equivalent to 0.12 ppm of triflumizole 14 days after treatment. In the cucumber plants, imidazole ring cleavage in triflumizole occurred as the initial step of the main metabolic pathway, giving a iV-formyl degradate which was deformylated to a major metabolite, lV-(4-chloro-2-trifluoro-methylphenyl)-propoxyacetamidine (FM-6-1), followed by depropylation at the ether linkage. © 1990, Pesticide Science Society of Japan. All rights reserved.