(from 400 to 305 g ha -1 ) without any loss of efficacy. Most likely, the occurring synergistic effects cause a noticeable increase in the toxicity of this system towards C. vulgaris compared to parent ILs. This result confirms that a more thorough evaluation of the ecotoxicity of new compounds is crucial in the process of development of novel herbicidal formulations that are not only effective in use but also safe for non-target species.