Insecticidal potential of fixed oil and hydrolate from Croton heliotropiifolius kunth against Aphis craccivora in cowpea

Cowpea Vigna unguiculata (L.) Walp. is a legume of high socio-economic importance in tropical and subtropical regions but is highly vulnerable to the black bean aphid, Aphis craccivora Koch (Hemiptera: Aphididae), which damages crops through phloem sap extraction and virus transmission. Farmers often rely on synthetic insecticides for effective management of this pest. Interest in sustainable botanical alternatives has increased over time due to their eco-friendly nature. This study evaluated the insecticidal potential of fixed oil and hydrolate from Croton heliotropiifolius against A. craccivora. Chemical analysis revealed distinct profiles: the fixed oil was rich in carboxylic acids, particularly butanoic acid and N-methyl anthranilate, while the hydrolate contained oxygenated monoterpenes such as linalool, terpinen-4-ol, and 1,8-cineole. Mortality bioassays showed LC50 values of 219.4 mL·L−1 for fixed oil and 278.0 mL·L−1 for hydrolate after 72 h. Results indicate both extracts are promising sustainable alternatives to conventional insecticides and highlight the importance of chemical characterisation in developing effective natural pest management strategies.