Chaulagain Bhim, Contina Jean Bertrand, Mills Karasi, Seibel Rachel L, Mundt Christopher C
College of Agricultural Sciences, Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA.
Ecol Appl. 2022 Sep;32(6):e2631. doi: 10.1002/eap.2631. Epub 2022 Jun 16.
Diseases characterized by long distance inoculum dispersal (LDD) are among the fastest spreading epidemics in both natural and managed landscapes. Management of such epidemics is extremely challenging because of asymptomatic infection extending at large spatial scales and frequent escape from the newly established disease sources. We compared the efficacy of area- and timing-based disease management strategies in artificially initiated field epidemics of wheat stripe rust and complemented with simulations from an updated version of the spatially explicit model EPIMUL, using model parameters relevant to field epidemics. The model was further used to expand the number of epidemic mitigations beyond that feasible to incorporate in the field. The field experiment was conducted for 2 years in two locations having different climatic conditions. Culling and protection treatments were applied at different times after epidemic initiation and to different spatial extents surrounding the outbreaks. In each experiment, treatments were replicated four times in plots 33.5 m long and 1.52 m wide with a 0.76 × 0.76 m inoculated focus centered within each plot. Disease gradients were assessed along the center lines of the plots at 1.52 m intervals both upwind and downwind from the focus. Both field and simulation results indicated that control measures applied over the entire population were highly effective in suppressing the epidemics by more than 99% but may not always be logistically and economically feasible at large spatial scales. Comparison between the variable sized treatment areas and application timings suggested that implementing contiguous premises (CP) cull at 1 day after first sporulation in the outbreak focus reduced rust by 52% and 60% in Corvallis and Madras, respectively. However, altering the cull size did not significantly affect the disease epidemic development, which suggested that early timing had a greater influence in suppressing the epidemics than did increased area of application. However, sufficiently large, treated areas may compensate for a delay in application timing to some extent. Results from these replicated treatments may help to devise appropriate management strategies for other LDD pathogens.
以长距离接种体传播（LDD）为特征的疾病是自然和人工管理景观中传播速度最快的流行病之一。由于无症状感染在大空间尺度上蔓延且经常从新建立的病源逃脱，此类流行病的管理极具挑战性。我们比较了基于面积和时间的疾病管理策略在人工引发的小麦条锈病田间流行中的效果，并使用与田间流行相关的模型参数，通过空间明确模型EPIMUL的更新版本进行模拟来补充。该模型进一步用于扩展流行病缓解措施的数量，超出了在田间可行的范围。田间试验在两个气候条件不同的地点进行了两年。在疫情开始后的不同时间，对疫情爆发点周围不同空间范围进行了剔除和保护处理。在每个实验中，处理在长33.5米、宽1.52米的地块中重复四次，每个地块中心有一个0.76×0.76米的接种中心。在距接种中心上风向和下风向每隔1.52米沿着地块中心线评估病害梯度。田间和模拟结果均表明，对整个种群实施的控制措施在抑制疫情方面非常有效，抑制率超过99%，但在大空间尺度上，在后勤和经济上可能并不总是可行的。不同大小处理区域和应用时间的比较表明，在疫情爆发点首次产孢后1天实施连续场所（CP）剔除，在科瓦利斯和马德拉斯分别使锈病减少了52%和60%。然而，改变剔除面积对病害流行发展没有显著影响，这表明早期实施比增加应用面积对抑制疫情的影响更大。然而，足够大的处理区域在一定程度上可以弥补应用时间的延迟。这些重复处理的结果可能有助于为其他长距离传播病原体制定适当的管理策略。
