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标题：Moderately decreasing fertilizer in fields does not reduce populations of cereal aphids but maximizes fitness of parasitoids
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作者：Fei Qiao ; Quan-Feng Yang ; Rui-Xing Hou 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2021
卷号：11
期号：1
页码：2517
DOI：10.1038/s41598-021-81855-8
出版社：Springer Nature
摘要：Abstract Examination of the tradeoff between the extent of decreasing nitrogen input and pest suppression is crucial for maintaining the balance between essential yield and an efficient, sustainable pest control strategy. In this study, an experiment with four manipulated nitrogen fertilizer levels (70, 140, 210, and 280 kg N ha −1 = conventional level) was conducted to explore the effects of decreasing nitrogen on cereal aphids ( Sitobion avenae and Rhopalosiphum padi ) (Hemiptera: Aphididae), Aphidiinae parasitoids (Hymenoptera: Braconidae: Aphidiinae), and body sizes of parasitoids. The results indicated that nitrogen application, in the range of 70–280 kg N ha −1 , has the potential to impact the populations of cereal aphids and their parasitoids. However, both differences between densities of cereal aphids and their parasitoids in moderate (140–210 kg N ha −1 ) and those in high nitrogen input (280 kg N ha −1 ) were not significant, and the parasitism rate was also unaffected. A higher parasitism rate reduced population growth of the cereal aphid ( S. avenae ). Additionally, a moderate decrease of nitrogen fertilizer from 280 to 140–210 kg N ha −1 maximized the body sizes of Aphidiinae parasitoids, indicating that a moderate decrease of nitrogen fertilizer could facilitate biocontrol of cereal aphid by parasitoids in the near future. We conclude that a moderate decrease in nitrogen application, from 280 to 140–210 kg N ha −1 , does not quantitatively impact the densities of cereal aphids or the parasitism rate but can qualitatively maximize the fitness of the parasitoids.
其他摘要：Abstract Examination of the tradeoff between the extent of decreasing nitrogen input and pest suppression is crucial for maintaining the balance between essential yield and an efficient, sustainable pest control strategy. In this study, an experiment with four manipulated nitrogen fertilizer levels (70, 140, 210, and 280 kg N ha −1 = conventional level) was conducted to explore the effects of decreasing nitrogen on cereal aphids ( Sitobion avenae and Rhopalosiphum padi ) (Hemiptera: Aphididae), Aphidiinae parasitoids (Hymenoptera: Braconidae: Aphidiinae), and body sizes of parasitoids. The results indicated that nitrogen application, in the range of 70–280 kg N ha −1 , has the potential to impact the populations of cereal aphids and their parasitoids. However, both differences between densities of cereal aphids and their parasitoids in moderate (140–210 kg N ha −1 ) and those in high nitrogen input (280 kg N ha −1 ) were not significant, and the parasitism rate was also unaffected. A higher parasitism rate reduced population growth of the cereal aphid ( S. avenae ). Additionally, a moderate decrease of nitrogen fertilizer from 280 to 140–210 kg N ha −1 maximized the body sizes of Aphidiinae parasitoids, indicating that a moderate decrease of nitrogen fertilizer could facilitate biocontrol of cereal aphid by parasitoids in the near future. We conclude that a moderate decrease in nitrogen application, from 280 to 140–210 kg N ha −1 , does not quantitatively impact the densities of cereal aphids or the parasitism rate but can qualitatively maximize the fitness of the parasitoids.