Yugi J.O.¹ , Khatoro R.T.² , Aketch C.O.³ , Gitonga N.M.⁴

1 School of Science and Technology, University of Kabianga, P. O Box 2030 - 20200. Kericho, Kenya
2 School of Environmental Studies, University of Eldoret, P. O. Box 1125 - 30100, Eldoret, Kenya
3 Kenya National Examination Council, P. O. Box 73598-00200, City Square, Nairobi-Kenya
4 School of Biological Sciences, Karatina University, P. O. Box 1957 - 10100 Karatina, Kenya
Author    Correspondence author
Journal of Mosquito Research, 2026, Vol. 16, No. 1   
Received: 01 Feb., 2026    Accepted: 27 Feb., 2026    Published: 10 Mar., 2026

This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Botanicals are targets for green insecticides and alternatives to synthetic insecticides. In this study, a randomized experimental design with control was used to evaluate in vitro toxicity level (LC₅₀ and LC₉₀) of crude methanol and hexane Urtica massaica leaf, stem and root extracts on immature stages of Anopheles gambiae. 100 eggs, larvae or pupae were exposed to doses of 80 mg/100mls (e/w), 40 mg/100mls (e/w), 20 mg/100mls (e/w), 10 mg/100mls (e/w), 5 mg/100mls (e/w), 2.5 mg/100mls (e/w) of the extracts in clear plastic containers measuring 6 cm × 5.7 cm × 3.5 cm. Each container held 33 mls of a dose and either 33 eggs, larvae or pupae. The experiments were replicated four times. The set ups were left to stand overnight except that of eggs that stood for 48hrs. Mortality was assessed at the end of the period. It was found that methanol extracts were more toxic than hexane and leaf and root extracts were more toxic than stem extracts. Dose and solvent of extraction significantly influenced mortality (p < 0.05) of all stages for methane and hexane extracts except for hexane root extracts (p > 0.05) used against L3s. Since calculated goodness of fit was greater than the critical value (χ² = 22.4; df = 22; p < 0.05) for all cases, the null hypothesis was rejected and the conclusion that U. massaica crude extracts was toxic to immatures of An. gambiae in vitro was adopted. It is concluded that U. massaica crude extracts are toxic against immatures of An. gambiae in vitro.

 

Urtica massaica; Methanol; Hexane; Lethal effect; Anopheles gambiae