The toxicity of a new natural insecticide, Spinosad, was assessed against Daphnia pulex (Leydig) using a demographic approach. Data were also generated for the commonly used insecticide, diazinon as a comparison. Exposure to Spinosad led to a concentration-dependent decline in survival, birth rate (b), net reproductive rate (Ro), and intrinsic rate of increase (rm). Population extinction occurred after exposure to spinosad concentrations > 10 ug/l . Generation time, doubling time and death rate all increased with increasing spinosad concentrations. Spinosad was approximately 7 times less toxic than diazinon to D. pulex based on intrinsic rate of increase. Although Spinosad is a new safer insecticide in terms of it’s effects on biological controls in agroecosystems, it still is toxic to Daphnia and as such it should be used cautiously near fresh water systems.
Species 1: Daphnia pulex (water flea)
Keywords: Spinosad, Ecotoxicology
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA