Behavioral preference and antennal responses induced by commercial essential oil formulations and their components in the German cockroach (Blattodea: Ectobiidae)

This study evaluates the antennal responses and behavioral preference of 3 strains of the German cockroach (Blattodea: Ectobiidae), Blattella germanica (L.) (S, D, and E), against 6 commercial essential oil-based formulations (Essentria, EcoVia, Excite-R, ER-22, Garscentria, and Orange Guard) and 8 individual components using electroantennography (EAG) and a two-choice olfactometer bioassay. Significant strain-specific differences in antennal sensitivity were observed, with strain E displaying the highest sensitivity, followed by strain D, while strain S demonstrated the least. Notably, Essentria elicited the strongest antennal responses and was least preferred by all strains at all concentrations, except for strain S at lower concentrations. EcoVia, Excite-R, and Orange Guard exhibited increased avoidance of the treatment only at the highest tested concentration (1,000 µg/µL), with EcoVia prompting higher treatment avoidance in strains D and E, Excite-R in strain E, and Orange Guard in strain S. In contrast, ER-22 demonstrated a significant increase in treatment avoidance for strain S at 1,000 µg/µL and for strain D even at 1 µg/µL. Garscentria did not significantly alter preference in any strain. A positive correlation between antennal responses and the level of treatment avoidance was observed, particularly for Essentria, suggesting that antennal sensitivity may predict olfactory-driven behavioral choices. These findings provide critical insights into the behavioral and physiological dynamics of strain-specific pest responses, emphasizing the importance of tailored approaches in pest management strategies.