The abundance of parasitoids in the oil palm plantation is greatly influenced by the host and food availability.However, studies on the main diet or food sources of the adult parasitoid wasp, Dolichogenidea metesae of the oil palm pest, Metisa plana is still lacking. This study investigated the diet of adult D. metesae sampled from Good Agricultural Practices (GAP) and non-GAP plantations through metagenomic analysis by using a trnL marker. A total of 761 145 food plant trnL sequences were generated from 12 samples of the parasitoids collected from four plantations. No significant differences (p=0.683) were observed for diversity (Shannon-Wiener index (H') of 0.12-1.22, p=0.68) among the total 62 OTU's of the food plant species when compared between the GAP and Non-GAP plantations. Polygonaceae was the most abundant plant family (59.95%), followed by Asteraceae (10.15%) and Acanthaceae (7.51%). The Antigonon leptopus, Paraprenanthes oligolepis, Asystasiella neesiana and wild banana (Musa itinerans) were among the most dominant plant species consumed by adult D. metesae. We recommend that these dominant food plant species for the D. metesae should be planted widely in the oil palm plantations to enhance the population abundance of D. metesae for successful Integrated Pest Management (IPM) practices.