Spinosyn D 17-pseudoaglycone is an acid degradation product produced by selective hydrolysis of the more labile forosamine saccharide in the 17-position in spinosyn D, the minor component of commercial product, Spinosad. Spinosyn D 17-pseudoaglycone is only weakly active as an insecticide as the forosamine moiety is considered essential for potent activity. Despite the importance of spinosyns as agro-chemical insecticides and more recently as animal health products, there are few published reports of the biological activity or the levels of spinosyn D 17-pseudoaglycone in animals or in the environment.