Metabolism of a Phenylurea Fungicide, Pencycuron [1-(4-chlorobenzyl)-1-cyclopentyl-3-phenylurea] in Rice Plants

• Published in: Journal of Pesticide Science Vol. 12; no. 3; pp. 435 - 443
• Main Authors: KUROGOCHI, Shin, TAKASE, Iwao, YAMAGUCHI, Isamu, MISATO, Tomomasa
• Format: Journal Article
• Language: English; Japanese
• Published: Tokyo Pesticide Science Society of Japan 01.01.1987; Japan Science and Technology Agency
• ISSN: 1348-589X; 1349-0923
• DOI: 10.1584/jpestics.12.435

The metabolic fate of pencycuron [1-(4-chlorobenzyl)-1-cyclopentyl-3-phenylurea] in rice plants was investigated with [phenyl-U-14C] compound. When the leaves were treated with 14C-pencycuron radiocarbon gradually penetrated into the leaf tissues and part of them showed an acropetal movement. Most radiocarbon was, however, retained on the leaf surface. Pencycuron always remained as a major component (52% of the applied dose after 40 days) and its metabolites were relatively minor in amount (7% of the applied dose). The metabolites identified were: 1-cyclopentyl-3-phenylurea (IV), 1-(4-chlorobenzyl)-3-phenylurea (V), 1-(4-chlorobenzyl)-1-(cis-3-hydroxycyclopentyl)-3-phenylurea (XI) and its trans isomer (XII), and glucosides of (XI) and (XII). Unextractable radiocarbon increased with time from 0.9% (1 day) to 16.5% (40 days). When 14C-pencycuron was sprayed twice on rice plants before heading and at the heading stage, radioactive residues in rice grains were found 0.56ppm as a pencycuron equivalent, but the radiocarbon was mainly localized in the bran (85%). Intact pencycuron was detected 0.018ppm in hulled rice and 0.003ppm in polished rice. Radiocarbon in grains mainly remained as an unextractable bound residue.