Climate change will have several consequences for agro-systems, one of which will concern changes to the development of pathogens. Because of the losses it causes, particularly in organic farming, Monilinia laxa is an important pathogen affecting apricot crops. This study focuses on the consequences of climate change regarding blossom and twig blight (Monilinia laxa) of apricot. To achieve this, a Climatic Index of cumulated Blight risk (CIB) was built, to obtain the weighted sum of blossom blight incidence throughout the blooming period. An epidemiological model to calculate the incidence of blossom blight during every potentially infectious episode and based on biological parameters, was calibrated using a trap pot experiment where trees were placed in orchards and subject to various meteorological conditions. The CIB derived from this model was evaluated on field data, and was shown to be a robust and useful tool to predict the effects of climate change on the development of apricot blight. Then, using the CIB with a phenological model to predict blooming periods in the future, we estimated the risks of apricot blight until 2100 on four contrasted apricot cultivars and in three geographical zones under climate change scenarios RCP 4.5 and 8.5. This study revealed different effects of climate change depending on the cultivar and altitude. Apricot trees would bloom earlier (up to a difference of 50 days between 1950 and 2100) under climate change. Under the combined effects of these shifts of blooming period and changing climatic conditions, late cultivars such as Bergarouge might see a reduction in the risk of blossom blight (down to 31%) because of warmer but dryer blooming periods. Other varieties (e.g.: Bergeron) could experience an increase in this risk by up to 27% with a shift of the blooming period towards rainier conditions at the highest altitudes. The results of this study could be used to anticipate future changes as well as be used at present as a decision-support tool for farmers.

中文翻译：

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气候变化下法国南部杏花枯病的未来发展

气候变化将对农业系统产生若干后果，其中之一将涉及病原体发展的变化。由于它造成的损失，特别是在有机农业中，松散念珠菌是影响杏作物的重要病原体。本研究侧重于气候变化对杏花和枝叶枯萎病（Monilinia laxa）的影响。为了实现这一点，建立了累积枯萎风险 (CIB) 的气候指数，以获得整个开花期开花枯萎病发生率的加权总和。使用诱捕盆实验校准在每个潜在传染性事件期间计算开花枯萎病发生率的流行病学模型，该模型基于生物参数进行校准，其中树木被放置在果园中并受到各种气象条件的影响。从该模型得出的 CIB 已根据现场数据进行了评估，结果表明它是一种强大且有用的工具，可用于预测气候变化对杏疫病发展的影响。然后，使用带有物候模型的 CIB 来预测未来的开花期，我们在气候变化情景 RCP 4.5 和 8.5 下估计了四个对比杏品种和三个地理区域直到 2100 年的杏疫病风险。这项研究揭示了气候变化的不同影响，取决于品种和海拔高度。在气候变化下，杏树会更早开花（1950 年和 2100 年之间最多相差 50 天）。在这些花期变化和气候条件变化的综合影响下，由于较温暖但较干燥的开花期，诸如 Bergarouge 等晚熟品种的花枯病风险可能会降低（降至 31%）。其他品种（例如：Bergeron）的这种风险可能会增加高达 27%，随着开花期向最高海拔的多雨条件转变。这项研究的结果可用于预测未来的变化，以及目前用作农民的决策支持工具。