Plant-derived biopesticides are components of integrated pest management that offer alternatives to conventional synthetic insecticides. In the present study, methanolic extracts of Chromolaena odorata (Asteraceae), Garcinia kola (Clusiaceae), Pueraria montana (Fabaceae), and Taraxacum officinale (Asteraceae) were evaluated against the first instars, the third instars, and adults of the Colorado potato beetle, Leptinotarsa decemlineata, in no-choice arenas. The extracts were applied to 1.39 cm2 leaf disks cut from healthy potato leaves in four concentrations (stock, high, medium and low) alongside a control (methanol-only treatment). Percentage leaf damage, leaf area remaining after exposure to the beetle, and feeding inhibition against the test insects were measured at 24 and 48 h. The efficacy of the plant materials varied significantly among plant species and concentration levels within species. The first instars consumed significantly less leaf area when treated with C. odorata and G. kola and moderately less at higher doses of P. montana and T. officinale than the control after 48 h of exposure. The third instars fed consistently less at the two highest doses of C. odorata and G. kola, and moderately less at the highest dose of P. montana. The adults caused significantly less damage across all doses of C. odorata, G. kola, and T. officinale; to the contrary, leaf disks treated with P. montana were severely impacted. Feeding deterrence was lower for the third instars compared to the first instars and the adults. Third instars is a rapidly growing, but not very mobile, developmental stage in the Colorado potato beetle. Therefore, for them feeding on distasteful, but still nutritionally suitable, foliage may be a less risky strategy compared to seeking alternative food sources. Among the four extracts, C. odorata and G. kola had the strongest effect across all three developmental stages tested. Therefore, they may be suitable for inclusion in the integrated pest management program directed against the Colorado potato beetle.