Largemouth bass ( Micropterus salmoides ) is an important freshwater‐cultured species in China. M. salmoides rhabdovirus (MSRV) is a devastating pathogen that causes high mortality (exceeding 90% in acute outbreaks) in largemouth bass fry, posing a severe threat to the global largemouth bass aquaculture industry. To address the urgent demand for rapid, on‐site MSRV detection, two multienzyme isothermal rapid amplification (MIR...