| Summary: | The rice weevil (<i>Sitophilus oryzae</i>) is a pest of stored grain products such as rice, wheat, and corn. Essential oils represent a green environmentally-friendly alternative to synthetic pesticides for controlling stored-product insect pests. <i>Launaea taraxacifolia</i> is a leafy vegetable plant found in several parts of Nigeria. The leaves are eaten either fresh as a salad or cooked as a sauce. The essential oil obtained from fresh leaves of <i>L. taraxacifolia</i> was obtained by hydrodistillation and analyzed by gas chromatography/mass spectrometry (GC-MS). Twenty-nine compounds were identified, accounting for 100% of the oil composition. The major component classes were monoterpene hydrocarbons (78.1%), followed by oxygenated monoterpenoids (16.2%), sesquiterpene hydrocarbons (2.1%), oxygenated sesquiterpenoids (0.3%), and non-terpenoid derivatives (3.3%). The leaf essential oil was dominated by monoterpene hydrocarbons including limonene (48.8%), sabinene (18.8%), and (<i>E</i>)-β-ocimene (4.6%), along with the monoterpenoid aldehyde citronellal (11.0%). The contact insecticidal activity of <i>L. taraxacifolia</i> essential oil against <i>Sitophilus oryzae</i> was carried out; median lethal concentration (LC<sub>50</sub>) values of topical exposure of <i>L. taraxacifolia</i> essential oil were assessed over a 120-h period. The LC<sub>50</sub> values ranged from 54.38 μL/mL (24 h) to 10.10 µL/mL (120 h). The insecticidal activity of the <i>L. taraxacifolia</i> essential oil can be attributed to major components limonene (48.8%), sabinene (18.8%), and citronellal (11.0%), as well as potential synergistic action of the essential oil components. This result showed <i>L. taraxacifolia</i> essential oil may be considered as a useful alternative to synthetic insecticides.
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