Abstract Use of neonicotinoid insecticides as seed treatments has been prohibited in the EU. As a consequence, concerns of lost production have been raised among producers. It remains, however, unclear to what extent the ban has increased pest attacks and crop damage, and reduced yield and farm profit. It is also unclear to what extent alternative, non-chemical options can protect crops. Flea beetles (Chrysomelidae: Alticini) are the main pests targeted by insecticide seed treatments in spring oilseed rape (Brassica napus L.). Over three years, we conducted 23 field experiments in which we compared seeds treated with neonicotinoids with untreated seeds, grown at normal or doubled sowing rates. The experiments were established during a range of sowing times at the same time as the hosting farmer sowed, which also allowed us to assess the impact of sowing date. We measured flea beetle activity density, crop plant density, cotyledon damage, crop yield and relative economic performance. Flea beetle activity density was eight times higher in 2014 than in 2016, with intermediate activity in 2015. Neonicotinoid seed treatment, increased sowing rate and an earlier sowing date all reduced crop damage. Seed treatment decreased crop yield loss by 521 kg ha−1 and relative profit loss by 144 Euro ha−1 in 2014, but had no effect on yield or profit in 2015–2016. Increased sowing rate did not affect yield, but decreased profit in 2015 (−138 Euro ha−1) and 2016 (−114 Euro ha−1), mainly due to higher costs for seed. Earlier sowing date was consistently associated with higher yield and profit. Our results put prophylactic seed treatments in question, as they gave lower yield losses in only one year out of three. Earlier sowing and somewhat higher sowing rate emerge as viable alternative pest management practices. Because management outcomes depended on pest pressure, which varied from year to year, crop damage prognosis tools are needed based on improved understanding of the population ecology of crop pests, to support the growers’ decisions and avoid unnecessary use of insecticides.

中文翻译：

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未经新烟碱类种子处理的春油菜病虫害管理和产量

摘要 欧盟禁止使用新烟碱类杀虫剂作为种子处理剂。因此，生产商对生产损失的担忧有所增加。然而，目前尚不清楚该禁令在多大程度上增加了害虫侵袭和作物损害，并降低了产量和农场利润。目前还不清楚替代的非化学选择可以在多大程度上保护作物。跳蚤甲虫（Chrysomelidae：Alticini）是春季油菜（Brassica napus L.）中杀虫剂种子处理的主要害虫。三年多来，我们进行了 23 次田间试验，将用新烟碱类药物处理的种子与以正常播种率或双倍播种率生长的未处理种子进行了比较。试验是在一定范围的播种时间与寄宿农民播种的同时建立的，这也使我们能够评估播种日期的影响。我们测量了跳蚤甲虫的活动密度、作物植株密度、子叶损伤、作物产量和相对经济表现。2014 年跳蚤甲虫的活动密度是 2016 年的 8 倍，2015 年的活动处于中等水平。新烟碱类种子处理、增加播种率和提前播种都减少了作物损害。2014 年种子处理使作物产量损失减少了 521 kg ha-1，相对利润损失减少了 144 Euro ha-1，但对 2015-2016 年的产量或利润没有影响。播种率增加并未影响产量，但 2015 年（-138 欧元公顷-1）和 2016 年（-114 欧元公顷-1）的利润下降，主要是由于种子成本较高。较早的播种日期始终与较高的产量和利润相关。我们的结果对预防性种子处理提出了质疑，因为他们只在三年中的一年中降低了产量损失。早播和稍高的播种率成为可行的替代害虫管理实践。由于管理结果取决于每年不同的害虫压力，因此需要基于对作物害虫种群生态的深入了解的作物损害预测工具，以支持种植者的决定并避免不必要地使用杀虫剂。