The examination of the compatibility between agricultural practices and biocontrol activities is crucial for establishing an efficient, eco-friendly, and sustainable pest management program. In this study, we examined the population dynamics of two specialist aphids, the English grain aphid (Sitobion avenae) on potted wheat and the pea aphid (Acyrthosiphon pisum) on potted alfalfa, as well as the biocontrol activity of a generalist predator, the harlequin ladybird beetle (Harmonia axyridis). We investigated their responses to the presence of the intercropping partner plant species (alfalfa and wheat, respectively) through plant volatiles or visual cues at three nitrogen fertilizer levels in a greenhouse. In the absence of the predator, the English grain aphid population growth rate increased significantly with increasing nitrogen levels, whereas the pea aphid population increased significantly more slowly in response to high nitrogen levels. The English grain aphid and pea aphid population dynamics were unaffected by the presence of the intercropping partner. However, the presence of the intercropping partner enhanced the control of both aphid populations by the harlequin ladybird beetle. Increasing nitrogen fertilizer levels decreased the predation rates, which were otherwise increased by the intercropping partner. The beneficial effects of the intercropping partner were eventually non-existent at the highest nitrogen level tested. These results imply that the interaction between the presence of intercropping partner and the nitrogen fertilizer application affects the biocontrol activity of the natural enemies of insect pests. Thus, the compatibility between agricultural intensification and biocontrol strategies in integrated pest management programs need to be investigated.

中文翻译：

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增加施氮量抑制间作伙伴植物促进的生物防治活动

检查农业实践和生物防治活动之间的兼容性对于建立高效、环保和可持续的害虫管理计划至关重要。在这项研究中，我们检查了两种专科蚜虫的种群动态，即盆栽小麦上的英国谷物蚜虫 ( Sitobion avenae ) 和盆栽苜蓿上的豌豆蚜虫 ( Acyrthosiphon pisum )，以及一种多面手捕食者丑角的生物防治活动。瓢虫甲虫（Harmonia axyridis）。我们通过温室中三种氮肥水平的植物挥发物或视觉线索调查了它们对间作伙伴植物物种（分别为苜蓿和小麦）的反应。在没有捕食者的情况下，英国谷物蚜虫种群增长率随着氮含量的增加而显着增加，而豌豆蚜虫种群对高氮含量的反应显着更慢。英国谷物蚜虫和豌豆蚜虫种群动态不受间作伙伴存在的影响。然而，间作伙伴的存在增强了丑角瓢虫对两种蚜虫种群的控制。增加氮肥水平会降低捕食率，否则间作伙伴会增加捕食率。在测试的最高氮水平下，间作伙伴的有益影响最终不存在。这些结果意味着间作伙伴的存在与氮肥施用之间的相互作用影响了害虫天敌的生物防治活性。因此，需要研究综合虫害管理计划中农业集约化和生物防治策略之间的兼容性。