Abstract
Spinosad is a common insecticide not only in organic but also conventional farming. It is a natural derived product from the fermentation of bacteria with a broad ranging control spectrum. The present study, carried out in the orchards of Research Centre Laimburg (Italy), aims to determine the residue decline behaviour of spinosad on apples and to determine different application strategies that results in a residue level not exceeding 0.01 mg/kg. This limit is often requested by European retailers and organic associations. The results show that 1 and 2 treatments, at application rates of 216 g/ha and the last treatment at least applied 20 days before harvest, ensures residue quantities below 0.01 mg/kg. Introduction Spinosad is a naturally derived insecticide produced through the fermentation of the bacteria Saccharopolyspora spinosa which occurs in nature and is not genetically engineered. It is comprised of two complex multi-ring molecules each with a different sugar attached to the central ring structure. These two molecules are very similar in composition and are referred to as spinosyn A and spinosyn D. Commercial formulations typically consist of a mixture of spinosyn A (CAS Registry No. 131929-60-7) and spinosyn D (CAS Registry No 131929-63-0) in a ratio of approximately 85:15 (Mertz,