Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331-2902, USA.
Ecol Appl. 2011 Mar;21(2):321-8. doi: 10.1890/10-1004.1.
Understanding landscape effects on disease spread can contribute to the prediction and control of epidemic invasions. We conducted large-scale field experiments with wheat stripe rust, which is caused by a wind-dispersed rust fungus. Three landscape heterogeneity variables were altered: host frequency (mixtures of susceptible and resistant plants), host patch size (different plot sizes), and size of initial disease focus (attained by artificial inoculation). Assessments of disease prevalence at different distances from the disease foci were used to quantify effects of landscape variables. We expected that a low frequency of susceptible hosts, small host patch sizes, and small initial disease foci would reduce secondary inoculum levels and thus suppress disease spread. Low host frequency and small initial disease foci greatly reduced epidemic spread. We did not detect an effect of host patch size on disease spread, though artificial inoculations did not allow us to measure the potential for small patches to escape infection under conditions of random deposition of initial inoculum. Our results suggest that, for diseases epidemiologically similar to wheat stripe rust, epidemic invasions may be suppressed by decreasing host frequency, limiting the size of initial outbreak foci, and applying control measures soon after epidemic establishment.
了解景观效应对疾病传播的影响有助于预测和控制传染病的入侵。我们用小麦条锈病进行了大规模野外实验，这种病是由一种随风传播的锈菌引起的。我们改变了三个景观异质性变量：宿主频率（易感染和抗性植物的混合物）、宿主斑块大小（不同的斑块大小）和初始病源焦点大小（通过人工接种获得）。通过评估不同距离处的疾病流行率来量化景观变量的影响。我们预计，低频率的易感染宿主、小的宿主斑块大小和小的初始病源焦点将减少二级接种物的水平，从而抑制疾病的传播。低宿主频率和小的初始病源焦点大大降低了传染病的传播。我们没有发现宿主斑块大小对疾病传播的影响，尽管人工接种不能使我们在初始接种物随机沉积的情况下测量小斑块逃避感染的可能性。我们的研究结果表明，对于流行病学上类似于小麦条锈病的疾病，通过降低宿主频率、限制初始爆发焦点的大小以及在传染病爆发后尽快采取控制措施，可以抑制传染病的入侵。
