FATE OF [DIFLUBENZURON-C-14 ON COTTON AND IN SOIL

Aqueous suspensions and oil emulsions of a commercial [14C]diflubenzuron (N-[[(4-chlorophenyl)amino]carbonyl]-2,6-difluorobenzamide) formulation (Dimilin W-25) remained on the leaf surface of greenhouse-treated plant tissues. Absorption, translocation, and metabolism of the [14C]diflubenzuron were not significant. Less than 0.05% of the applied 14C was found in newly developed plant tissues 28 days after spray treatment. [14C]Diflubenzuron was degraded in soil. After 91 days, biometer flask studies showed that 28% of the 14C incorporated into the soil as [14C]diflubenzuron was recovered as 14CO2. Major dichloromethane-soluble soil residues were identified as unreacted [14C]diflubenzuron and [14C]4-chlorophenylurea. A minor unknown degradation product cochromatographed with 2,6-difluorobenzoic acid. Insoluble 14C-residues increased with time and represented 67.8% of the residual 14C in the soil 89 days after treatment. Cotton plants grown for 89 days in [14C]diflubenzuron-treated soil contained only 3% of the 14C applied to the soil. Small quantities of acetonitrile-soluble [14C]4-chlorophenylurea were isolated from the foliar tissues. Root tissues contained small amounts of [14C]diflubenzuron and trace quantities of a minor 14C-product that chromotographed similarly to 2,6-difluorobenzoic acid. Most of the 14C in the plant tissues (84-93%) was associated with an insoluble residue fraction 89 days after treatment. © 1979.