Essential Oils: Repellency and Toxicity against Imported Fire Ants (Hymenoptera: Formicidae).

flower essential oils (EOs) blue Egyptian (EO-), chamomile German CO2 (EO-), and chamomile German (EO-) and the pure compound α-bisabolol were evaluated against red imported fire ants (RIFA), Buren, black imported fire ants, Forel (BIFA), and hybrid imported fire ants (HIFA) for their repellency and toxicity. A series of serial dilutions were tested starting from 125 µg/g until the failure of the treatment. Based on the amount of sand removed, EO- showed significant repellency at dosages of 7.8, 7.8, and 31.25 µg/g against RIFA, BIFA, and HIFA, respectively. EO- was repellent at 3.9, 7.8, and 31.25 µg/g against BIFA, RIFA, and HIFA, whereas α-bisabolol was active at 7.8, 7.8, and 31.25 µg/g against BIFA, HIFA, and RIFA, respectively. DEET (N, N-diethyl-meta-toluamide) was active at 31.25 µg/g. Toxicity of EOs and α-bisabolol was mild to moderate. For EO- LC values were 93.6 and 188.11 µg/g against RIFA and BIFA; 98.11 and 138.4 µg/g for EO-; and 142.92 and 202.49 µg/g for EO-, respectively. The LC of α-bisabolol was 159.23 µg/g against RIFA. In conclusion, EOs and α-bisabolol offer great potential to be developed as imported fire ant repellents.