Eco-toxicity of different agricultural tank-mix adjuvants

Abstract

Adjuvants are often used to improve the efficiency of plant protection products. However, there is concern that these compounds themselves might result in ecotoxicological effects. To investigate this concern, we compare the toxicity of different agricultural tank-mix adjuvants for two standard test organisms, i.e. the water flea Daphnia magna and the honey bee Apis mellifera. Daphnia trials comprised tests at 1, 5 and 20 times the normal prescribed label dosage. It is found that at 48h, the novel polymer-based adjuvant Squall is significantly less harmful to D. magna compared to traditional surfactant or oil-based adjuvants. For A. mellifera, we tested topical exposure to label-rate, five and twenty times label-rate. After 96h exposure to polymer- and oil based adjuvants no statistically significant harmful effects were observed. The trisiloxane-based adjuvants, however, did significantly increase bee mortality at higher dose rates, indicating a higher toxicity of these specific compounds.