Powerful Plant Oil Combo Kills Flies, Safe for Others

Jenn Hoskins
15th March, 2024

Powerful Plant Oil Combo Kills Flies, Safe for Others

Image Source: Natural Science News, 2024

Key Findings

  • A mix of lemongrass oil and star anise killed houseflies better than synthetic insecticide
  • This natural blend was three times more effective and not harmful to bees or fish
  • The oils caused physical damage to the flies, explaining their potent insecticidal action
In recent years, the fight against insect pests has become increasingly complex. The overuse of synthetic insecticides has led to resistance in pests, environmental damage, and health concerns for humans and non-target organisms. This has spurred a search for safer, more sustainable alternatives. One promising avenue is the use of essential oils (EOs) from plants, which have shown potential as bioinsecticides due to their natural origin and reduced side effects. Researchers from King Mongkut's Institute of Technology Ladkrabang have made significant progress in this area with a study[1] examining the adulticidal effects of lemongrass and star anise essential oils, as well as their major constituents, against the common housefly. Houseflies are not only a nuisance but also vectors for various diseases, making their control a public health priority. The study employed gas chromatography-mass spectrometry (GC-MS) to identify the main components of the EOs: geranial in lemongrass and trans-anethole in star anise. Building upon earlier research that demonstrated the effectiveness of EOs and their constituents against other pests like mosquitoes[2][3], the team tested single and mixture formulations of these oils against houseflies. They found that almost all mixture formulations outperformed single formulations and the synthetic insecticide α-cypermethrin in killing adult houseflies. Notably, a blend of 1.0% lemongrass EO and 1.0% trans-anethole was particularly potent, achieving a 100% mortality rate with a knockdown time (KT50) of 3.2 minutes and lethal time (LT50) of only 0.07 hours, which was three times more effective than α-cypermethrin. Scanning electron microscopy (SEM) provided insights into the mechanism behind this adulticidal action. The researchers observed morphological aberrations in the treated houseflies, including deformed antennae and mouthparts, changes in pigmentation, and damage to the pseudotracheae, which are involved in feeding and respiration. An essential aspect of this study was the consideration of non-target species, specifically the stingless bee and the guppy fish. The safety of EOs towards these beneficial organisms is crucial as they play important roles in ecosystems—the bees in pollination and the guppies in water ecosystems. The findings were encouraging: all single and mixture formulations of the EOs were non-toxic to these non-target species, while α-cypermethrin showed high toxicity. These results align with previous research that highlighted the potential of natural compounds like monoterpenes, found in many EOs, as biopesticides[4]. Moreover, the study confirms the growing body of evidence suggesting that plant-based bioinsecticides could offer effective control strategies without the drawbacks associated with synthetic insecticides[5]. The implications of this study are significant. The mixture of lemongrass EO and trans-anethole presents a natural and sustainable alternative to traditional synthetic insecticides for controlling housefly populations. Furthermore, the lack of toxicity to non-target species suggests that such mixtures could be integrated into pest management programs with minimal environmental impact. In conclusion, the research by King Mongkut's Institute of Technology Ladkrabang offers a promising solution to the problem of insect pest control. By harnessing the synergistic effects of plant-derived essential oils, we can develop more effective, eco-friendly methods to combat pests while safeguarding human health and the environment.

BiochemEcologyPlant Science


Main Study

1) Adulticidal synergy of two plant essential oils and their major constituents against the housefly Musca domestica and bioassay on non-target species.

Published 15th March, 2024


Related Studies

2) Essential Oils for a Sustainable Control of Honeybee Varroosis.


3) Combinations of plant essential oils and their major compositions inducing mortality and morphological abnormality of Aedes aegypti and Aedes albopictus.


4) Pesticidal Activity and Mode of Action of Monoterpenes.


5) Plant-Based Bioinsecticides for Mosquito Control: Impact on Insecticide Resistance and Disease Transmission.


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