Abstract Most agricultural production systems face challenges with multiple arthropods, plant pathogens and/or weed species, but few studies address the impact of multiple pests when developing integrated pest management programs. In onion production, onion thrips and bacterial bulb rot are primary constraints, and choice of onion cultivar, fertility regime and insecticide use may be important tactics to manage both. In a two-year study in New York, two independent field trials were conducted concurrently. The first experiment included either a moderately thrips-resistant cultivar (‘Avalon’) or a thrips-susceptible cultivar (‘Bradley’), multiple nitrogen rates (0, 67, 84, 118, and 151 kg/ha) and either a season-long, action threshold-based insecticide program or no insecticide program (20 treatments total). The second experiment included the same cultivars and insecticide programs but evaluated phosphorous rates (0, 56, 112, and 168 kg/ha) (16 treatments total). In both trials and years, ‘Avalon’ experienced lower thrips densities, but suffered 58% more bacterial rot, which reduced onion yields overall by 9%. Nitrogen and phosphorus fertilizer had limited impact on onion thrips, bacterial rot, and onion yield. Although, higher rates of nitrogen fertilizer increased bacterial bulb rot in 2017. In both years, low rates of fertilizer (67 kg/ha N or 56 kg/ha P) produced statistically similar yields to plants supplemented with the highest rates of fertilizer. Insecticide use reduced thrips densities and increased bulb yield in both years but did not consistently reduce bacterial bulb rot. Therefore, growers can optimize onion production by reducing rates of fertilizer and using an action-threshold based insecticide program. Furthermore, our results indicate that IPM programs should be evaluated to consider multiple biotic constraints simultaneously within an agricultural production system as IPM tactics can be counterproductive.

中文翻译：

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病虫害综合治理面临的挑战：洋葱蓟马和洋葱球茎腐烂的案例研究

摘要 大多数农业生产系统面临多种节肢动物、植物病原体和/或杂草种类的挑战，但很少有研究在制定综合虫害管理计划时解决多种害虫的影响。在洋葱生产中，洋葱蓟马和细菌球茎腐烂是主要限制因素，洋葱栽培品种的选择、生育制度和杀虫剂的使用可能是管理这两者的重要策略。在纽约进行的一项为期两年的研究中，同时进行了两项独立的现场试验。第一个实验包括中等蓟马抗性品种（'Avalon'）或蓟马易感品种（'Bradley'），多种氮肥施用量（0、67、84、118 和 151 千克/公顷）和一个季节- 长期、基于行动阈值的杀虫剂计划或无杀虫剂计划（共 20 次处理）第二个实验包括相同的栽培品种和杀虫剂程序，但评估了磷含量（0、56、112 和 168 千克/公顷）（总共 16 个处理）。在试验和几年中，“阿瓦隆”的蓟马密度较低，但细菌腐烂率增加了 58%，这使洋葱的总体产量降低了 9%。氮磷肥对洋葱蓟马、细菌腐烂和洋葱产量影响有限。尽管如此，2017 年较高的氮肥用量增加了细菌球茎腐烂。在这两年中，低肥料用量（67 公斤/公顷 N 或 56 公斤/公顷 P）与补充最高肥料的植物产生统计上相似的产量。在这两年中，杀虫剂的使用降低了蓟马密度并增加了鳞茎产量，但并没有始终如一地减少细菌性鳞茎腐烂。所以，种植者可以通过降低肥料用量和使用基于行动阈值的杀虫剂计划来优化洋葱生产。此外，我们的结果表明，应评估 IPM 计划以同时考虑农业生产系统内的多种生物约束，因为 IPM 策略可能会适得其反。