Purpose of Review

Forest tree diseases are a major contributor to forest degradation and loss of productivity. They are often quite complex in their causation (etiology), especially in the case of forest syndromes, i.e. diseases with multiple causes and concurrent symptoms. Traditionally, to prove pathogenicity of a microbial agent, and thus correctly diagnose the etiology of a disease, plant pathologists must satisfy all of the so-called Koch’s postulates, as mandated by their deontological code. This review examines whether this approach is still current.

Recent Findings

Koch’s postulates state that a pathogen is a microorganism that, after being isolated in pure culture, can reproduce the disease when it is inoculated into a healthy plant. Over the decades, plant pathologists as well as medical scientists have discovered that these postulates are not always applicable in their entirety and that, furthermore, novel approaches based on molecular biology can be very helpful in uncovering relationships between microbes and diseases that are not easily proven using Koch’s postulates.

Summary

I conclude that Koch’s postulates are not a viable approach for many forest tree diseases and propose a set of new guidelines, based on the preponderance of the evidence principle, to integrate this proven approach and bring it into the twenty-first century.

中文翻译：

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复杂的森林树木疾病——超出科赫假设的诊断

 审查目的

林木病害是森林退化和生产力损失的主要原因。它们的因果关系（病因学）通常相当复杂，特别是森林综合症，即具有多种原因和并发症状的疾病。传统上，为了证明微生物的致病性，从而正确诊断疾病的病因，植物病理学家必须满足所有所谓的科赫假设，这是他们的义务论准则所要求的。本次审查探讨了这种方法是否仍然有效。

 最近的发现

科赫假设指出，病原体是一种微生物，在纯培养物中分离出来后，在接种到健康植物中时可以繁殖疾病。几十年来，植物病理学家和医学科学家发现，这些假设并不总是完全适用，此外，基于分子生物学的新方法可以非常有助于揭示微生物与疾病之间不易证明的关系使用科赫假设。

 概括

我的结论是，科赫的假设对于许多林木疾病来说并不是一种可行的方法，并基于证据优势原则提出了一套新的指导方针，以整合这种经过验证的方法并将其带入二十一世纪。