Rethinking tree disease aetiology: from classical pathogens to complex pathological systems and emerging diagnostic approaches

The aetiology of tree diseases developed from a classical single-pathogen-based model to one of greater complexity and integration, which acknowledges interaction between microbial communities, host physiology, and environmental stress. Conventional models based on Koch’s postulates are often inadequate for forest pathologies due to multifactor interactions, e.g., non-cultivable organisms and synergistic ecological processes. More specific and detailed analysis of disease trends is now being possible because of new diagnostics like metagenomics, metabarcoding, and artificial intelligence-assisted remote sensing. This paper describes a systems approach of forest tree disease aetiology and discusses further the limitations of reductionist paradigms. For effective management and comprehension of emerging tree diseases, we recommend the unification of molecular technology, ecological habitats, and forecasting equipment with a focus on the necessity of holistic diagnostic methods.