GREENHOUSE APPLICATOR AND HARVESTER EXPOSURE TO PESTICIDES

Permethrin insecticide was applied to greenhouse-grown roses using conventional, high-volume (1700 L/ha) and air-assisted, electrostatic, reduced-volume (34 L/ha) spraying systems. The electrostatic, reduced-volume application resulted in greater efficiency in foliar deposition; a one-half rate of pesticide applied electrostatically was equivalent to a full-rate applied conventionally. The conventional application resulted in greater contamination of non-target surfaces of the aisle ways and bed centers. Dislodgeable foliar residue was removed by two techniques, viz., an aqueous surface extraction and a dry mechanical brushing. The ratio of mechanically-removed to surfaced-extracted residue was 0.126 and 0.148 for the reduced-volume and conventional treatments, respectively. Applicator and harvester monitoring found dermal exposure to be below detection limits for both application techniques. Pesticide concentration in the applicator breathing zone air was higher during electrostatic spraying (188 vs. 8 μg/m³). Concentrations of permethrin in greenhouse air during and immediately after electrostatic application were significantly higher (110 fold) than those after conventional spraying. After 105 minutes post application, air concentrations from either application technique were below detection (0.15 μg/m³).