Insecticidal potential of seven commonly available alkaloids against melon thrips (Thrips palmi Karny) was investigated through in vivo experiments and the bioactivity was explained via in silico approaches. In vivo screening showed highest mortality of T. plami larvae for reserpine (43%), closely followed by tropinone (41%) after 24 h of incubation. After 48 h, tropinone surpassed reserpine with 83% mortality, indicating its prolonged insecticidal activity. A detailed bioassay of tropinone revealed its LC₅₀ values as 1187.9 and 686.9 µg mL^-1 after 24 and 48 h, respectively. While studying the molecular interactions between the alkaloids and four physiologically important target proteins of T. palmi, tropinone demonstrated the highest ligand efficiency and lowest predicted inhibitory constant, particularly when forming complexes with CathB protein. However, binding energy calculations of the docked complexes showed most favorable binding of reserpine with CathB. To clear the ambiguity, considering both binding energy and ligand efficiency as the evaluation parameters, a molecular dynamics study was carried out, which predicted higher stability of CathB-tropinone complex than CathB-reserpine complex in terms of the total energy of the system. These in silico findings aligned well with the in vivo results, confirming tropinone as a promising candidate for effective thrips management programs.