Spinosad is an insecticide with a completely unique and novel mode of action. It is used in a great variety of crops: fruit, vegetables, and ornamental plants. Its dissipation was studied in three vegetables: cabbage (the cultivar Stonehead), carrot (cv. Perfekcja) and onion (cv. Wolska). The vegetables were sprayed with a dose of 96 g a.i. ha-1 of spinosad and collected after 1, 3, 5, and 7 days. The residues were analyzed using high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection after purification on a column with methanol. Elements were determined with flame atomic absorption spectroscopy (FAAS), and the determinations were made on the 1st and 7th day after spraying. The determined amounts of spinosad were in the range of 0.943-0.072 mg kg-1 for carrot and onion, respectively, on the 7th day. Spinosad decomposed completely in cabbage, and the highest level of the pesticide after 7 days remained in carrot, although the shape of all decomposition curves is quite similar. Most elements in onion were on significantly higher levels after sprays than in the control variant, opposite to cabbage, where higher levels of the analyzed elements were determined in the control. Concentrations of the elements determined in carrot were statistically significant for manganese, iron and magnesium. The spinosad decomposition time and the content of elements depend on the species of vegetables. The amount of spinosad on day 7 found in onion and cabbage was equal to the Maximum Residue Level (MRL) available in the literature.

22.2.2017