Dithiocarbamate spray residues on lettuces, tomatoes, berryfruits, and apples

After experimental or commercial spray programmes, thiocarbamate fungicide residues were determined on lettuces, boysenberries, tomatoes, blueberries, and apples. Highest residues were recorded on lettuce, less on boysenberries, and least on blueberries, tomatoes, and apples. Rates of decay and estimated half lives (6-9 days) were similar for maneb, mancozeb, zineb, and thiram. In most instances residues following mancozeb spraying were higher than for maneb, the difference being greatest for lettuce and least for tomatoes. Results are discussed in relation to current New Zealand tolerance levels and waiting periods.