“Candidatus Liberibacter solanacearum” (Lso) (=“Candidatus Liberibacter psyllarous”) is an uncultured, phloem-limited bacterium that is associated with zebra chip disease (ZC) in potato (Solanum tuberosum L.) and transmitted by the potato psyllid (Bactericera cockerelli (Šulc)). Vector density and timing of infection have been shown to affect ZC prevalence at harvest; however, little work has been done on disease development during storage. Here we confirm with field-cage trials that ZC prevalence at harvest was greater with increased time between inoculation and vine kill. Moreover, we show that with Pacific Northwest growing conditions, ZC can develop over time during storage. Plants inoculated 2 to 3 weeks before vine kill showed little or no ZC symptoms in tubers at harvest, but higher prevalence of symptoms after 3 months in storage. For plants inoculated at 4 to 5 weeks before vine kill, tubers exhibited notable symptoms at harvest, but still showed evidence of symptom development after storage. Plants inoculated within 1 week before vine kill exhibited little or no risk of ZC in tubers at harvest or after storage. Higher vector density tended to contribute to ZC prevalence, but was far less important than timing of infection. These results underscore the potential danger of underestimating ZC prevalence at harvest for tubers being stored long term, and suggest that plants at risk of Lso infection should be protected from potato psyllids until at least 2 weeks before vine kill.

中文翻译：

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马铃薯木虱载体密度和感染时间对收获后和贮藏期间斑马片病发展的影响

“ Candidatus Liberibacter solanacearum”（Lso）（=“ Candidatus Liberibacter psyllarous”）是未经培养的韧皮部限制细菌，与马铃薯（Solanum tuberosum L.）的斑马片病（ZC）有关，并由马铃薯木虱（Bactericera）传播小鸡（Šulc））。业已证明，病媒密度和感染时机会影响收获时ZC的流行。然而，在储存过程中关于疾病发展的工作很少。在这里，我们通过田间笼养试验证实，收获时ZC患病率随接种和杀死葡萄藤之间时间的增加而增加。此外，我们显示，随着西北太平洋地区的生长条件，ZC在储存过程中会随着时间而发展。在藤蔓杀死前2至3周接种的植物在收获时的块茎中几乎没有ZC症状，但在储存3个月后该症状的患病率更高。对于在藤本植物杀死前4至5周接种的植物，块茎在收获时表现出明显的症状，但在贮藏后仍显示出症状发展的迹象。在藤本植物杀死前1周内接种的植物在块茎收获时或储存后几乎没有ZC风险。较高的载体密度往往有助于ZC流行，但远不如感染时机重要。这些结果强调了长期保存块茎时低估收获时ZC发生率的潜在危险，并建议应保护处于Lso感染风险的植物免受马铃薯木虱危害，直到至少2周后才能杀死葡萄。