High tunnels are large protective structures used for season extension of many crops, including raspberries. These structures are often covered in plastic films to reduce and diffuse ultraviolet light transmission for pest and disease control, but this may also affect the photodegradation and efficacy of pesticides applied under these tunnels. We compared the residue levels of ten insecticides under three tunnel plastics with varying levels of UV transmission and open field conditions. Raspberry plants placed in research-scale tunnels were treated with insecticides and residues on fruit and foliage were monitored for one or two weeks in early 2015 and early and late 2016. Plastics that reduce UV transmission resulted in 50% greater residues of some insecticides compared to transparent plastics, and 60% compared to uncovered tunnels. This increased persistence of residues was evident within 1 day and remained consistently higher for up to 14 days. This pattern was demonstrated for multiple insecticides, including bifenthrin, esfenvalerate, imidacloprid, thiamethoxam, and spinosad. In contrast, the insecticide malathion degraded rapidly regardless of the plastic treatment, indicating less sensitivity to photodegradation. Bioassays using insecticide-treated leaves that were under UV-blocking plastic revealed higher mortality of the invasive fruit pest, Drosophila suzukii, compared to leaves that were uncovered. This indicates that the activity of pesticides under high tunnels covered in UV-reducing plastics may be prolonged, allowing for fewer insecticide applications and longer intervals between sprays. This information can be used to help optimize pest control in protected culture berry production.

中文翻译：

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紫外线透射率降低，延长了受保护的树莓生产中的杀虫剂寿命

高高的隧道是用于保护许多农作物（包括覆盆子）的季节的大型保护性结构。这些结构通常用塑料膜覆盖，以减少和扩散紫外线传播，以控制病虫害，但这也可能影响在这些隧道下施用的农药的光降解和功效。我们比较了三种隧道塑料在紫外线透射和露天条件不同的情况下，十种杀虫剂的残留水平。在研究规模的隧道中对覆盆子植物进行了杀虫剂处理，并在2015年初以及2016年初和2016年底对水果和树叶上的残留物进行了一到两周的监测。与紫外线辐射相比，减少紫外线传播的塑料残留量比某些杀虫剂高50％。透明塑料，与未发现的隧道相比，占60％。残留物持久性的这种增加在1天之内就很明显，并且在多达14天的时间内一直保持较高水平。对多种杀虫剂（包括联苯菊酯，乙草戊酸酯，吡虫啉，噻虫嗪和多杀菌素）证明了这种模式。相比之下，无论采用何种塑料处理方式，杀虫剂马拉硫磷都会迅速降解，表明对光降解的敏感性较低。使用在紫外线防护下使用杀虫剂处理过的叶子进行的生物测定表明，入侵性果害的死亡率更高，表明对光降解的敏感性较低。使用在紫外线防护下使用杀虫剂处理过的叶子进行的生物测定显示，入侵性果害的死亡率更高，表明对光降解的敏感性较低。使用在紫外线防护下使用杀虫剂处理过的叶子进行的生物测定显示，入侵性果害的死亡率更高，与未发现的叶子相比，果蝇铃木（Drosophila suzukii）。这表明在延长紫外线照射的塑料覆盖的高空隧道下，农药的活性可能会延长，从而减少了杀虫剂的使用，并延长了两次喷雾之间的间隔。该信息可用于帮助优化保护性浆果生产中的害虫控制。