Background: Houseflies are global pests that promote the spread of a few harmful illnesses in humans.
Compared to synthetic chemicals, phytochemical compounds are effective and safe alternative insecticides.
Objective: To evaluate the potential efficacy of Rosmarinus officinalis, Piper nigrum, Cinnamomum verum,
Cyperus rotundus, Melaleuca alternifolia, and Aloe vera essential oils (EOs) as larvicides, i.e., inhibitors of
M. domestica emergence.
Material and Methods: Housefly larvae were obtained from the insectary of the Medical and Molecular
Entomology Section, Faculty of Science, Benha University. Bioassays were performed at 27±2°C and 70–
80% humidity to determine the effects of variable concentrations of six EOs on larvae using ingestion and
contact-treated filter paper. To determine the phytochemical composition, EOs were subjected to GC-MS
analysis.
Results: All investigated EOs exhibited high to moderate toxicity against house fly larvae. Third-instar
larvae suffered 100% mortality at 10% concentration of EOs in experiments using ingestion method in
treated rearing medium, while 91.11-100% mortality was recorded at 10% concentration of EOs using
contact-treated filter paper. The best results were obtained using R. officinalis and C. verum EOS for
killing housefly larvae, delaying larval and pupal development, and increasing the inhibition rate (100%).
Besides, M. alternifolia EO was less effective (73.3%, and 91.11 mortality) in ingestion method, and
contact bioassays, respectively. The GC-MS analysis revealed that R. officinalis and C. verum EOs had more
monoterpenes (α-Pinene and eucalyptol), and flavonoid compounds (cinnamonaldehyde), respectively.
Conclusion: It was concluded that R. officinalis, and C. verum EOs are effective insecticides against house
fly larvae.