A loop-mediated amplification (LAMP) assay developed previously to specifically identify Clavibacter michiganensis subsp. michiganensis, the causal agent of bacterial canker of tomato, was compared with a commercial lateral flow immunoassay, three PCR assays, and culturing on agar medium for efficacy in detecting the pathogen in pepper and tomato tissues and tomato seeds. The LAMP assay was as effective in identifying C. m. michiganensis-positive tomato seed and tissue samples as the Cmm ImmunoStrip®. The LAMP assay was performed using a handheld real-time fluorescence-monitoring device (Smart-DARTTM) and the iQTM5 Multicolor Real-Time PCR Detection System to compare both systems. Both devices produced equivalent results, thus demonstrating the potential of this LAMP detection system for field detection. A side-by-side comparison of the C. m. michiganensis-LAMP with the Cmm ImmunoStrip® assay, two conventional PCR assays, using Cmm5/6 and PSA8/R primer sets, and one quantitative PCR assay (primers RZ_ptssk 10/11, probe RZ_ptssk12), showed that the C. m. michiganensis-LAMP/Smart-DARTTM assay can provide real-time portable in-field test results comparable to accepted standards. These results, combined with the specificity established previously, suggest that this LAMP assay can be an alternative to current diagnostic tests designed to detect C. m. michiganensis. This LAMP assay could be seamlessly integrated into standardized testing regimens, such as those of the European and Mediterranean Plant Protection Organization (EPPO), International Seed Federation (ISF), and commercial seed companies, as the definitive C. m. michiganensis confirmatory test, following isolation of colonies by plating.