Residues of maneb in tomato and their persistence during cooking and storage

Tomato plants, grown in greenhouse were sprayed with an aqueous suspension of ETU-free 14C-maneb (5 mg/10 μCi/plant) three times at weekly intervals. Thirty-five days after the first application, maneb residues were highest in leaves (352 ppm) and lowest in fruits (0.12 ppm). ETU values were generally low and the fruit concentration was 0.01 ppm. It is noted that ETU residues were only those generated in 35 days from ETU-free maneb. Cooking fruits reduced maneb concentration by 27% and increased ETU from 0.010 to 0.014 ppm. Analysis of commercial preparations of maneb over a period of 18 months showed a decline of maneb concentration by 10% and 40% in closed and open packages, respectively. (author). 10 refs, 3 tabs