Stephen F. Goodwin

purchased. Too often, this leads to the decision to use the chemicals ‘just in case’ even when their application may cause more harm than good. Alternatives that could be used as part of an IPM strategy include crop rotation and diversity, inter-row planting, management of planting schedules, tillage and irrigation according to the minimisation of pest dangers, and biological strategies, such as trap crops and biological control agents, leaving the selective use of certain insecticides as a last resort. In theory, the EU has made the IPM approach compulsory for all crops as of the beginning of this year, but member states have been slow in implementing the directive. What is less easy to control or even understand is what systemic pesticides do once they have entered the soil. Generally, it has emerged that their effects on the natural environment are much more subtle and complex than what the simplistic toxicity tests could account for. The WIA highlights a number of ‘knowledge gaps’ surrounding these products. Intriguingly, the first big gap is the lack of knowledge regarding the quantities of systemic pesticides that have been used. This kind of information is crucial for a more detailed assessment of the ecological impact, and it should be a straightforward political measure to make detailed information publicly accessible. Further weaknesses in our knowledge include the accumulation of pesticides in soil, water and sediments, which is well-screened in the Netherlands, and is starting to be better understood in a few other countries, e.g. Canada, but not everywhere else. Even less is known about the long-term fate of these substances and their metabolites, along with their chronic toxicity, sublethal effects, and any synergistic effects between those substances. As an international collaboration led by Nicolas Desneux from the INRA’s Institut Sophia Agrobiotech at SophiaAntipolis, France, has shown in a recent paper, the complex relationship between exposure time and toxic effects in ants, bees and termites further complicates the issues (Sci. Rep. (2014) 4, 5566, http://dx.doi. org/10.1038/srep05566). Thus, there are many questions to be answered while the partial EU moratorium on neonicotinoids continues. Only one thing appears to be clear already: applying systemic pesticides to all seeds regardless probably never was a good idea to begin with.