Bacterial wilt disease caused by Trinickia (Burkholderia) caryophylli poses a significant threat to carnation cultivation in many regions around the world, often leading to severe damage once established. In this study, we developed a BIO-PCR method with high sensitivity and accuracy to detect and quantify T. caryophylli in soil, enabling precise evaluation of pathogen contamination levels. Single PCR (using a touchdown PCR program) was performed using the bacterial cells pre-incubated in a selective liquid medium as a template. The detection limit for this assay was 3 colony-forming-units (cfu) per g dry mass soil. By combining the most probable number (MPN) method and touchdown BIO-PCR, T. caryophylli can be quantified simultaneously. We validated this method in carnation cultivation fields and found a correlation between the degree of disease in each field and the measured density of the bacteria. This method will help develop and establish effective pest control techniques because it targets only live T. caryophylli in soil and can measure the density with high sensitivity and accuracy.
