VIEW ARTICLE

Transcuticular Movement of Fungicides. Z. Solel, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel, and University of Guelph, Guelph, Ontario, Canada; L. V. Edgington, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel, and University of Guelph, Guelph, Ontario, Canada. Phytopathology 63:505-510. Accepted for publication 24 October 1972. DOI: 10.1094/Phyto-63-505.

Movement of fungicides through cuticle, chemically removed from apple leaves, was studied in a system in which a fungicide was applied to the external side of a cuticle, and the diffusion of the fungicide into potato-dextrose agar underneath the cuticle was bioassayed. In 24 hr, 0 to 87% of the dosage of fungicides applied to a cuticle disk had moved through it. Transcuticular movement of fungicides was more efficient with cuticles isolated from the abaxial than from the adaxial surface of leaves. Efficiency of transcuticular movement of benzimidazole fungicides decreased in the following order: thiophanate-methyl, thiophanate, benomyl, methyl 2-benzimidazolecarbamate (MBC), and thiabendazole (TBZ). Movement of triarimol, phenylmercurimonoethanol ammonium acetate, and carboxin was moderately rapid, although the last one was limited in movement through adaxial cuticle. Captafol, chlorothalonil, thiram, and captan exhibited relatively slow rates of transcuticular movement, particularly with abaxial cuticle. Dodine did not show transcuticular movement. Increasing the solubility of benomyl and TBZ in acidified water enhanced their transcuticular movement fourfold. Translaminar movement was evident with benomyl, MBC, thiophanate, and thiophanate-methyl, but not with captan, captafol, or chlorothalonil.