The influence of fungicide choice and row width on the appearance of dithiocarbamate residues in potato.

摘要

Dithiocarbamate residues are frequently found in food monitoring programmes in Slovenia. The effect of fungicide choice and time since last spraying on dithiocarbamate residues in potato tubers were studied in field trials during 2003-2005. 4 treatments were used in the trial: exclusive spraying with dithiocarbamate fungicides; alternate spraying with dithiocarbamate fungicide; spraying with non dithiocarbamate containing fungicide; and unsprayed control. 10 plants in the field and 5 kg of stored tubers were randomly sampled in consecutive sampling after the last spraying. The influence of row width on dithiocarbamate residues content of tubers at different depths was also studied. GC MS was used for determination of dithiocarbamates. Dithiocarbamate residues were found only in the year 2003. Results show that environmental conditions are the key factor leading to dithiocarbamate residues in potatoes. They have a larger influence than the quantity of active substance used or other measures taken. Use of good farming practice enables production of potatoes without residues in most years. Under certain climatic conditions residues are found despite use of technical recommendations and use of the correct interval between fungicide application and harvest.