Toxicity of chlorantraniliprole to the Collembola Folsomia candida : toxicodynamics and effects of organic matter content

Sammanfattning: Toxicity of pesticides to non-target organisms determines their impact on natural environments. And to find pesticides with a new, target-specific mode of action, which are safe to farmers and organisms in the surrounding environment, is important when developing new pesticides.In this study, toxicity of the insecticide chlorantraniliprole to the Collembola Folsomia candida was investigated, showing that the test animals were adversely affected by the compound. Toxicity was tested in two experiments; a reproduction test in four soils with different organic matter content, following the OECD Guideline 232, and a toxicodynamic test where mortality, mobility, reproduction and morphological changes were recorded.The reproduction test showed a lower toxicity of chlorantraniliprole in the high-organic soils compared to the low-organic. When organic matter content increased two times, the difference between the lowest and the highest EC50 and EC10 values was a factor of 5.3 and 8.4, respectively. pH did not seem to significantly affect toxicity, and organic matter content did not seem to affect the total number of juveniles produced.The toxicodynamic test showed a fast mode of action on mobility of F. candida, but not on mortality. Mobility decreased at the highest treatments of chlorantraniliprole already one day after the animals were introduced to the test vessels, but significant mortality was still not seen after almost three weeks. Reproduction was also adversely affected with a decline in the total number of juveniles produced at the higher treatments. The animals at the higher treatments also showed a possible compound induced reproduction stress, with faster egg laying. Morphological changes, such as affected antennas, increased steadily over time.Chlorantraniliprole shows high toxicity to some non-target organisms but is, with its new mode of action, still important in the development of more environmentally safe pesticides.