Marine seaweeds enriched with natural bioactive compounds have been utilized in the current study to alleviate Aphis craccivora infestation in cowpea. Insecticidal and repellent activities were evaluated with extracts from four macroalgae (Padina pavonica, Sargassum tenerrimum, Portieria hornemannii and Gracilaria corticata) against A. craccivora adults. Samples were extracted using Soxhlet extraction with solvents of varying polarity (methanol, chloroform, acetone and hexane). In leaf dip bio-assay P. pavonica methanolic extract (PPME) and P. hornemannii chloroform extract (PHCE) showed highest mortality (> 85%) of A. craccivora (at 1.6%) concentration after 72 h of treatment, when compared with other 16 different seaweed extracts. In repellency test, the PPME and PHCE showed constant repellent effect at 1.6 per cent concentration with an IBT (Index of Behavioral Tendency) value (0.238, 0.213, 0.288, 0.188 and 0.275) and (0.250, 0.275, 0.275, 0.225 and 0.238) after 4, 8, 12, 18 and 24 h of treatment, respectively. GC–MS/MS analysis of PPME and PHCE revealed the most likely active constituents hexadecenoic acid methyl ester, phytol, and n-hexadecanoic acid as potential insecticidal compounds. Additionally, these two extracts were utilized to evaluate their synergistic effects with ginger and basil oils. The highest synergistic effect was observed in PHCE + basil + ginger oil (Synergistic ratio (SR), 1.44) followed by PPME + basil + ginger oil (SR, 1.41). The selected two seaweeds exhibited good synergistic effect with ginger and basil oil against cowpea bean aphid in laboratory condition. Hence, these seaweed extracts would be an alternative botanical pesticide in the development of IPM module for the management of cowpea aphids.