Conclusion

This study evaluated the resistance status of B. germanica populations to fipronil in densely populated public environments. Given the widespread use of fipronil-based bait formulations, monitoring resistance in field populations is essential to preserve its effectiveness in urban pest management programs. The results demonstrated variation in susceptibility levels among populations, ranging from susceptible to moderately resistant phenotypes. Molecular analysis of randomly selected samples did not identify any previously validated point mutations known to play a major role in target-site resistance to fipronil. Although the A299S and A301S substitutions were detected in two populations, their contribution to resistance remains unclear. Overall, these findings indicate that fipronil continues to be an effective control agent in several environments; however, the observed reduction in susceptibility in some populations highlights the need for continuous resistance surveillance and the implementation of integrated pest management strategies to delay further resistance development.