Chemical composition, insecticidal activity and non-target effects of Sphagneticola trilobata (L.) Pruski essential oil against immature stages (egg, larvae and pupae) of dengue, filariasis, malaria vectors and four natural predators.

Vector control remains the most effective strategy for preventing serious diseases. The present research was undertaken to check the effectiveness of essential oil (EO) from Sphagneticola trilobata (L.) Pruski against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus mosquito species. The EO was tested at concentrations of 3.125, 6.25, 12.5, 25 and 50 μl/L. The oil demonstrated 85-100% ovicidal activity at 50 μl/L concentration against the eggs of all three species within 24 h; it was similar to that of temephos the positive control. It also showed strong larvicidal activity with LC values of 51.66, 129.58 and 25.88 μl/L within 24 h against the larvae of Anopheles, Aedes and Culex species respectively. However, no significant pupicidal activity was observed in any of the mosquito vectors. GC-MS analysis identified ten compounds, with terpene compound α-Pinene (84.57%) as the primary component; this compound may contribute significantly to the observed activity. Toxicity studies revealed that the EO from S. trilobata had no adverse effects on the tested natural predators. The EO was formulated for field application and tested in a laboratory setting; it showed potential larvicidal and ovicidal activities without harming natural predators. Future research should prioritize isolating these compounds, investigating their mode of action and evaluating field applications to develop a viable mosquito control product derived from S. trilobata. The present study reports that EO from S. trilobata is a potent and safe insecticidal agent against the three tested mosquito vectors.