Cultivated potato, Solanum tuberosum (Solanaceae), is a key host of the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae). This important defoliating pest is recalcitrantly resistant to multiple classes of synthetic insecticides when overused. Hence, there is a continual search for novel active ingredients, such as biopesticides, which hold promise but are poorly explored. Here, variable doses [stock, high, mild, and low at 0.2, 0.1, 0.05, and 0.01 g/mL respectively] of methanolic seed extract of Garcinia kola (Clusiaceae) or bitter kola were tested for ovicidal effect, antifeedance, and repellency against the Colorado potato beetle. Behaviors of the first and third instars, and adults were investigated in dual and no-choice Petri dish experiments, alongside olfactory response to treated leaves in a wind tunnel. The extract was not ovicidal. All three tested stages consumed significantly less from stock-, high-, and medium-dose treated leaves compared to the low-dose and control leaves. The results were consistent for dual-choice and no-choice experiments. Garcinia kola deterrence intensity depended on beetle stage, and exposure time; it remained high (>80%) at stock/high doses, declined swiftly at medium, transient at low, and absent in control. These outcomes support observed feeding attenuation and higher antifeedance at increasing dosage that limit leaf damage to < 10%. The beetles differed in wind-tunnel response, taking a longer time to reach the initial 30-cm observation point for untreated leaves, while treatment effects and odds of reaching the final 50-cm observation point were nonsignificant. Thus, G. kola seed extract has promising short-distance behavior-modifying properties against Colorado potato beetle, and may delay resistance associated with synthetics, while minimizing their attendant deleterious effects on non-target species.