Background <p><i>Caryedon serratus</i> (Olivier, 1790) (Coleoptera: Chrysomelidae) is a major groundnut pest that infests groundnut kernels. This study aimed to extract phytochemicals from <i>Carum copticum</i> using a Soxhlet extractor with methanol as an organic solvent and to evaluate their efficacy against <i>C. serratus.</i></p> Results <p>Methanolic extract and its fractions showed significant adulticidal effects after 4&#xa0;days of treatment, with 87.11 ± 2.21% and 70.10 ± 2.52%, respectively. A sex ratio imbalance, extension or reduction of developmental phases, decreased fecundity, and reduced fertility. In comparison to the control, the hexane fraction produced fecundity averages of 55.33 ± 2.01 eggs, and the ethyl acetate fraction produced an average of 41 ± 0.25 eggs, corresponding to reductions in spawning rates of 52.93% and 63.25%, respectively. Gas chromatography–mass spectrometry (GC–MS) were used to identify the major bioactive chemicals in <i>C. copticum</i>, and there was thymol (C₁₀H₁₄O), 1-methylbenzene (toluene, C₁₀H₁₄), 7-oxabicycloheptane (C₁₀H₁₈O), 1-pentene4-methyl (C₆H₁₂), and octane (C₈H₁₈). <i>C. serratus</i> was exposed to three distinct concentrations of the plant's crude and fractions of extract of organic solvents (hexane, ethyl acetate, and methanol).</p> Conclusions <p>All concentrations caused substantial mortality in <i>C. serratus</i> eggs and adults. This study shows that the efficacy of <i>C. copticum</i> is due to the active chemicals present in the extract that can be employed as a biocontrol agent against the major pest <i>C. serratus</i>.</p>