Accumulation of Pesticides in Tomato Packinghouse Wastewater and the Influence of Integrated Pest Management on Reducing Residues
Water analyses from six commercial tomato packinghouse dump tanks in South Carolina revealed that metal and pesticide residues accumulate in the dump-tank water during daily operation. The amount that accumulated varied widely as follows: Asana (esfenvalerate), 0.3 to 13.8 ppb; Bravo (chlorothalonil), 0.1 to 2.7 ppm; copper, 2.0 to 7.3 ppm; and manganese, 0.1 to 2.5 ppm. Contamination appeared to be lowest when growers implemented integrated pest management (IPM) during production. In a subsequent controlled study, tomatoes were produced under the following pest-management practices: IPM protocol with pesticide applications based on scouting reports, modified IPM with one arbitrary pesticide application at bloom, and weekly pesticide application regardless of pest pressure. In a small-scale dump tank simulating commercial packinghouse operation, the water used for tomatoes that were produced with a weekly spray schedule had about 2 to 10 times the amount of pesticide and metal residues found in the water used for tomatoes grown under IPM protocol. Modified IPM protocol resulted in intermediate levels of residues. These results confirm that IPM field practices can reduce residues in tomato packinghouse wastewater.