TOMCAST and two models (risk hours and critical days) based on a generic infection model (GI model) were evaluated for the timing of fungicide application to control early blight (Alternaria solani) in field experiments. A five-year experiment was conducted at AU Flakkebjerg with the starch potato cultivars Kardal (2016 & 2017), Avarna (2019 & 2020), and Allstar (2021). Barley kernels infested with Alternaria solani were used to inoculate the potatoes. The disease was assessed weekly, starting from the onset of the first symptoms. The impact of disease development was quantified using the area under the disease progress curve (AUDPC), the relative area under the disease progress curve (rAUDPC) as well as starch yield. An economic analysis was done to determine the profitability of the models. Fungicide application significantly suppressed early blight development in comparison to untreated plots. The fungicide-treated plants gave higher yields (10–35%) than the untreated plants. Nevertheless, the models reduced fungicide use by an average of 37–49%, without any yield or economic penalty. Most fungicides were saved with the TOMCAST model, but disease control and yield were generally lower than in plots treated according to the GI-based models. Overall, our study emphasizes the economic importance of early blight and the necessity of applying fungicides to control it. We also show the possibility of significantly reducing fungicide use by using decision support systems. For the first time, we demonstrate the feasibility of using GI models to time fungicide application to control early blight.

TOMCAST 和基于一般感染模型（GI 模型）的两个模型（风险小时数和关键天数）在田间实验中评估了杀菌剂施用时间以控制早疫病（Alternaria solani ）。AU Flakkebjerg 对淀粉马铃薯品种 Kardal（2016 年和 2017 年）、Avarna（2019 年和 2020 年）和 Allstar（2021 年）进行了为期五年的实验。大麦粒被Alternaria solani侵染用于接种马铃薯。从出现第一个症状开始，每周对疾病进行评估。使用疾病进展曲线下面积 (AUDPC)、疾病进展曲线下相对面积 (rAUDPC) 以及淀粉产量来量化疾病发展的影响。进行了经济分析以确定模型的盈利能力。与未处理的地块相比，杀菌剂的应用显着抑制了早疫病的发展。经杀菌剂处理的植物比未经处理的植物产量更高 (10–35%)。尽管如此，这些模型平均减少了 37-49% 的杀菌剂使用量，而没有任何产量或经济损失。使用 TOMCAST 模型可以节省大部分杀菌剂，但病害控制和产量通常低于根据基于 GI 的模型处理的地块。全面的，我们的研究强调了早疫病的经济重要性以及应用杀菌剂控制它的必要性。我们还展示了通过使用决策支持系统显着减少杀菌剂使用的可能性。我们首次证明了使用 GI 模型来确定杀真菌剂施用时间以控制早疫病的可行性。