Institut Agro, University of Rennes, INRAE, IGEPP, 35000, Rennes, France.
Laboratoire Amiénois de Mathématique Fondamentale et Appliquée CNRS UMR 7352, Université de Picardie Jules Verne, 80039, Amiens, France.
Bull Math Biol. 2022 May 22;84(7):68. doi: 10.1007/s11538-022-01023-5.
Host diversification methods such as within-field mixtures (or field mosaics, depending on the spatial scale considered) are promising methods for agroecological plant disease control. We explore disease spread in host mixtures (or field mosaics) composed of two host genotypes (susceptible and resistant). The pathogen population is composed of two genotypes (wild-type and resistance-breaking). We show that for intermediate fractions of resistant hosts, the spatial spread of the disease may be split into two successive fronts. The first front is led by the wild-type pathogen and the disease spreads faster, but at a lower prevalence, than in a resistant pure stand (or landscape). The second front is led by the resistance-breaking type, which spreads slower than in a pure resistant stand (or landscape). The wild-type and the resistance-breaking genotypes coexist behind the invasion fronts, resulting in the same prevalence as in a resistant pure stand. This study shows that host diversification methods may have a twofold effect on pathogen spread compared to a resistant pure stand (or landscape): on the one hand, they accelerate disease spread, and on the other hand they slow down the spread of the resistance-breaking genotype. This work contributes to a better understanding of the multiple effects underlying the performance of host diversification methods in agroecology.
生境混交（或视空间尺度而定的生境镶嵌）等宿主多样化方法是农业生态系统中控制植物病害的一种很有前途的方法。我们探索了由两种宿主基因型（敏感和抗性）组成的宿主混合物（或生境镶嵌）中的疾病传播。病原体种群由两种基因型（野生型和抗性突破型）组成。我们表明，对于中等比例的抗性宿主，疾病的空间传播可能会分裂成两个连续的前沿。第一个前沿由野生型病原体主导，疾病传播速度比抗性纯系（或景观）更快，但流行率较低。第二个前沿由抗性突破型主导，其传播速度比抗性纯系（或景观）慢。在入侵前沿的后面，野生型和抗性突破型共存，导致与抗性纯系相同的流行率。本研究表明，与抗性纯系（或景观）相比，宿主多样化方法对病原体传播可能具有双重影响：一方面，它们加速了疾病的传播，另一方面，它们减缓了抗性突破型的传播。这项工作有助于更好地理解农业生态系统中宿主多样化方法表现的多种潜在影响。
