Plant-soil feedbacks can mediate aboveground plant–herbivore interactions by impacting plant chemistry. Given that soil legacies and agricultural practices are closely tied, a better understanding of soil legacy cascades and their application in pest management are needed. We tested how cover crop legacies alter resistance to fall armyworm (Spodoptera frugiperda Smith, Lepidoptera: Noctuidae) in maize (Zea mays L., Poales: Poaceae). We compared herbivore performance and behavior of fall armyworm larvae on maize grown after four cover crop treatments: a leguminous mycorrhizal cover crop (pea: Pisum sativum L., Fabales: Fabaceae), a nonleguminous mycorrhizal cover crop (triticale: x Triticosecale Wittm. Ex A. Camus, Poales: Poaceae), a nonleguminous nonmycorrhizal cover crop (radish: Raphanus sativus L., Brassicales: Brassicaceae), and no cover crops (fallow). Soil inorganic N was highest in pea treatments and lowest in triticale treatments, while maize AMF colonization was greatest when grown after mycorrhizal cover crops compared to nonmycorrhizal or no cover crops. Cover crop legacies altered the emission of maize volatiles and fall armyworm larvae oriented toward odors emitted by maize grown after radish more frequently than triticale in olfactometer assays. Additionally, larvae performed better and consumed more leaf tissue when feeding on maize grown after radish and poorest on plants grown after triticale. When damaged by fall armyworm, maize grown after triticale expressed higher levels of lipoxygenase-3 (lox3), while plants grown after radish upregulated maize proteinase inhibitor (mpi) gene expression. Our results highlight the importance of appropriate cover crop selection and suggest that triticale could strengthen maize resistance to fall armyworm.

中文翻译：

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覆盖作物土壤遗产改变玉米的植物化学和对秋粘虫（鳞翅目：夜蛾科）的抗性

植物 - 土壤反馈可以通过影响植物化学来调节地上植物 - 草食动物的相互作用。鉴于土壤遗产和农业实践密切相关，需要更好地了解土壤遗产级联及其在害虫管理中的应用。我们测试了覆盖作物遗产如何改变玉米（Zea mays L.，Poales：禾本科）对秋粘虫（Spodoptera frugiperda Smith，鳞翅目：夜蛾科）的抗性。我们比较了在四种覆盖作物处理后种植的玉米上秋粘虫幼虫的食草动物性能和行为：豆科菌根覆盖作物（豌豆：Pisum sativum L.，Fabales：豆科），非豆科菌根覆盖作物（黑小麦：x Triticosecale Wittm. Ex A. Camus，Poales：禾本科），一种非豆科非菌根覆盖作物（萝卜：Raphanus sativus L.，Brassicales：十字花科），并且没有覆盖作物（休耕）。土壤无机氮在豌豆处理中最高，在黑小麦处理中最低，而与非菌根或无覆盖作物相比，在菌根覆盖作物后种植的玉米 AMF 定殖最大。覆盖作物遗产改变了玉米挥发物和秋粘虫幼虫的排放，这些植物在嗅觉计测定中比黑小麦更频繁地种植萝卜后的玉米散发的气味。此外，幼虫在以萝卜后种植的玉米为食时表现更好，消耗更多的叶子组织，而以黑小麦后种植的植物为食时表现最差。当被秋粘虫破坏时，在黑小麦后生长的玉米表达了更高水平的脂氧合酶 3 (lox3)，而在萝卜后生长的植物上调了玉米蛋白酶抑制剂 (mpi) 基因的表达。