Ethylenethiourea (ETU) and ethylenethiuram monosulfide (ETM) in bean plants treated with 14C-maneb

The fate and magnitude of residues of maneb in bean plant (Vicia faba) were determined following fungicidal applications under conditions of local practice. 14C-maneb, diluted with ETU-free cold maneb to a final specific activity of 2 mCi/g was applied three times at weekly intervals. The total dose amounted to 12.23 mg/plant (25.76 μCi). Residues were extracted with chloroform-ethanol, water, EDTA and the unextractable residues were determined by combustion. Transformation products were identified and quantified by TLC. The data indicated that < 3% of the applied dose was found in the different parts of the plant. Chloroform-ethanol and water extractable residues showed a gradual increase in leaves, stem and roots of the plant. ETM appeared in water extracts of both leaves and stem. ETU was detected in both chloroform-ethanol and water extracts of leaves and stem 25 days after the first treatment. ETU and ETM were major metabolites in the dry seeds which showed a residue concentration of 0.05 ppm of which only 6% was water and chloroform-ethanol extractable. ETU contributed 25% of the extractable products. The bound material remained unidentified. (author). 7 refs, 1 fig., 8 tabs