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Anise and Fennel Essential Oils and Their Combination as Natural and Safe Housefly Repellents
Author(s)
Sittichok, Sirawut
Puwanard, Cheepchanok
Sinthusiri, Jirisuda
Moungthipmalai, Tanapoom
Murata, Kouhei
Date Issued
January 1, 2025
Type
Article
Abstract
Essential oils (EOs) are effective repellents and eco-friendly alternatives. We tested single and combination EOs of fennel and anise for repellency and stability against houseflies. All treatments were stored at 27 °C for up to 360 days. Efficacies were compared against α-cypermethrin as a reference. Safety bioassay used on two representative non-target species (guppies and earthworms) confirmed safety. The strongest repellency and stability, 100% repellency and RC50 of 0.4 mL/m3 on day 1, was achieved by a fennel + anise EO combination (1:1). After 360 days, these combinations remained effective (95% repellency), and RC50 = 0.8 mL/m3. The EO combinations were more effective than all single EOs and α-cypermethrin at all times, showing strong synergy with a synergistic repellent index of 2.4 to 3.3. This fennel + anise EO combination was more than 24 times more effective as a repellent than α-cypermethrin. Morphological damage included damaged antennae with twisted flagella and abnormal aristae. All single and combination EOs were not toxic to the non-targets and could be considered safe, whereas α-cypermethrin was highly toxic to them. Thus, the fennel + anise EO combination has great potential to be developed as a safe, natural repellent for managing housefly populations.
Citation
Insects, 16(1), 2025