Larvicidal activity, biochemical impact and chemical composition of Juniperus phoenicea essential oil on the vector of avian malaria Culiseta longiareolata.

Background objectives: The application of essential oils (EOs) as environmentally friendly tools for vector control has become a major focus in biopesticide research. This study aimed to characterize the chemical composition of the EO derived from Juniperus phoenicea L. harvested in the El Ma Labiodh region (Tebessa, Algeria) and to evaluate its larvicidal potential against the fourth larval instar of Culiseta longiareolata (Diptera: Culicidae).

Methods: The EO was extracted from dried leaves by hydrodistillation and characterized using gas chromatography-mass spectrometry (GC-MS). Its larvicidal activity was evaluated following the World Health Organization (WHO) standard protocol. Additionally, the effects of two lethal concentrations (LC25 and LC50) were assessed on detoxification enzymes activities, glutathione S-transferase (GST) and catalase (CAT), as well as on major biochemical components (proteins, lipids, and carbohydrates) in larval tissues across different exposure periods.

Results: Hydrodistillation yielded 0.56±0.03% EO, with GC-MS analysis identifying 51 compounds. Pinene (34.64%), Carene (15.26%), Limonene (13.82%), and Myrcene (3.85%) were the predominant constituents. The EO exhibited significant larvicidal activity, with mortality rates ranging from 5 to 100%, and LC25 and LC50 values of 38.14 ppm and 57.31 ppm, respectively. Toxicity was associated with the up regulation of detoxification mechanisms, evidenced by elevated GST and CAT activities, alongside notable alterations in the larvae's biochemical profiles.

Interpretation conclusion: These findings underscore the potential of J. phoenicea EO as a natural larvicide against Cs longiareolata, supporting its use as a sustainable tool for integrated mosquito control strategies.