Citrus Black Spot (CBS), caused by the ascomycete, Phyllosticta citricarpa, is a fruit, foliar, and twig spotting fungal disease affecting the majority of commercial cultivars of citrus. The disease causes cosmetic lesions, may cause fruit drop and P. citricarpa is considered a quarantine pathogen by some countries, impacting domestic and international trade of citrus fruit. Regulatory requirements affecting fruit trade exist even though there is no documented case of disease spread via infected fruit into previously disease-free areas. To clarify the risk of fruit as a potential pathway for the spread of CBS, we developed a quantitative, probabilistic risk assessment model. The model provides an assessment of all steps in the fruit pathway, including production, packinghouse handling, transportation, export-import distribution channels, and consumer endpoints. The model is stochastic and uses Monte Carlo simulation to assess the risk of P. citricarpa moving through all steps in the pathway. We attempted to use all available literature and information to quantitate risk at each point in the potential pathway and by sequentially linking all steps to determine the overall quantitative risk. In addition, we assessed climatological effects on incidence of diseased fruit at production sites and on fungal reproduction and infection, as well as criteria for establishment at endpoints. We examined ten case studies between exporting and importing locations/countries. Model results indicated fruit to be an epidemiologically insignificant means for CBS spread, even between producing countries where CBS occurs and CBS-free importing countries with disease-conducive climates. We created a second model to examine the introduction of infected plant material from countries where CBS occurs. This model demonstrated significant probability of introduction via such infected material. However, pathogen establishment and disease development was still restricted only to areas with conducive climatological conditions. We created a tool to quantitatively explore the viability of various potential pathways via combinations of CBS-present production sites and corresponding pathway endpoints, including environments conducive and non-conducive to CBS. The tool is provided to aid decision makers on phytosanitary risk relative to international trade of citrus fruit.

由子囊菌Phyllosticta citricarpa引起的柑橘黑斑病（CBS）是一种水果，叶面和嫩枝发现真菌病，影响了大多数商业柑橘品种。该病引起美容性病变，可能导致水果下降和柠檬酸假单胞菌在某些国家/地区被认为是检疫病原体，影响了柑橘类水果的国内和国际贸易。即使没有记录的疾病通过受感染的水果传播到先前无病地区的案例，也存在影响水果贸易的法规要求。为了阐明水果的风险是传播CBS的潜在途径，我们开发了定量的概率风险评估模型。该模型提供了对水果通路中所有步骤的评估，包括生产，包装车间处理，运输，进出口分配渠道和消费者终点。该模型是随机的，并使用蒙特卡洛模拟来评估柠檬酸假单胞菌的风险在路径的所有步骤中移动。我们尝试使用所有可用的文献和信息来量化潜在途径中每个点的风险，并通过依次链接所有步骤来确定总体定量风险。此外，我们评估了气候变化对生产现场病果发生率以及真菌繁殖和感染的影响，以及在终点建立的标准。我们检查了出口和进口地点/国家之间的十个案例研究。模型结果表明，即使在发生CBS的生产国与无CBS的具有致病性气候的进口国之间，水果对于CBS的传播在流行病学上意义不大。我们创建了第二个模型来检查来自发生CBS的国家的受感染植物材料的引入。该模型证明了通过这种感染材料引入的可能性很高。但是，病原体的建立和疾病的发展仍然仅限于气候条件有利的地区。我们创建了一个工具，用于通过CBS存在的生产场所和相应的途径终点（包括有利于和不利于CBS的环境）的组合来定量探索各种潜在途径的可行性。提供了该工具，以帮助决策者了解与柑橘类水果国际贸易有关的植物检疫风险。我们创建了一个工具，用于通过CBS存在的生产场所和相应的途径终点（包括有利于和不利于CBS的环境）的组合来定量探索各种潜在途径的可行性。提供了该工具，以帮助决策者了解与柑橘类水果国际贸易有关的植物检疫风险。我们创建了一个工具，用于通过CBS存在的生产场所和相应的途径终点（包括有利于和不利于CBS的环境）的组合来定量探索各种潜在途径的可行性。提供了该工具，以帮助决策者了解与柑橘类水果国际贸易有关的植物检疫风险。