Earthworm Pathology: An Overview of Diagnostic Approaches and Microbial Threats in Laboratory and Field Conditions

Abstract

Earthworms are vital ecosystem engineers that play fundamental roles in soil formation, nutrient cycling, organic matter decomposition, and the maintenance of soil fertility. Their ecological importance has led to the widespread adoption of vermiculture and vermicomposting technologies for sustainable waste management and agricultural productivity. However, the health and performance of earthworm populations can be adversely affected by a variety of diseases, parasites, pests, and environmental stressors that remain poorly documented and often overlooked. This review provides a comprehensive synthesis of current knowledge on the major biotic factors influencing earthworm health, with particular emphasis on economically important vermiculture species such as Eisenia fetida and Eudrilus eugeniae. The review examines bacterial diseases, fungal infections, viral associations, protozoan and helminthic parasites, and invertebrate pests including mites and predatory flatworms. In addition, physiological disorders associated with environmental stress, particularly acidic bed syndrome, moisture imbalance, poor aeration, and substrate deterioration, are discussed. The occurrence, symptoms, transmission pathways, ecological consequences, and management strategies associated with these health challenges are critically evaluated. Recent advances in microbiome research, metagenomics, and molecular diagnostics are highlighted for their potential to improve understanding of host–microbe interactions and disease detection in earthworm populations. The review also identifies significant knowledge gaps, including limited experimental validation of reported pathogens, inadequate disease surveillance, and insufficient information on disease dynamics under tropical vermiculture conditions. Emphasis is placed on integrated disease management, biosecurity measures, environmental monitoring, and sustainable vermiculture practices for maintaining healthy earthworm populations. By consolidating fragmented information and identifying future research priorities, this review serves as a valuable resource for researchers, soil biologists, and vermiculture practitioners working toward improved earthworm health, enhanced vermicomposting efficiency, and sustainable soil ecosystem management.