Waterhemp (Amaranthus tuberculatus (Moq.) J. D. Sauer) is one of the most competitive and herbicide-resistant weed species in soybean cropping systems across North America. While its competitive and adaptive traits are well-documented, its role as an alternative host for plant pathogens remains underexplored. This review synthesizes current knowledge on fungal, bacterial, viral, and nematode pathogens that infect waterhemp and examines the ecological and management implications of these interactions. We discuss how waterhemp may serve as a reservoir for inoculum, potentially influencing disease dynamics in soybean under changing climate conditions. Furthermore, we assess the potential of host-specific pathogens as biological control agents within the integrated weed management (IWM) approach. Despite promising experimental results, several barriers limit large-scale adoption of bioherbicides, including environmental sensitivity, narrow host specificity, challenges in mass production, and regulatory constraints. Understanding weed–pathogen interactions could inform dual-purpose strategies that reduce both weed pressure and disease risk in soybean systems. Further research is needed to optimize biocontrol scalability, assess climate-driven epidemiological shifts, and develop robust integrated weed and disease management approaches.
Rankrape et al. (Wed,) studied this question.