not in Young In the last few years, a new olive insect pest that infests the buds and leaves was recorded and identified as the olive buds moth/or jasmine moth (Palpita unionalis Hubner). Within a short period of time, the pest spread to an epidemic level in olive nurseries throughout the country. Many beneficial insects and pathogens were found, and recorded for the first time in Syria, in olive orchards and olive nurseries, as natural enemies of P. unionalis. The 1st and 2nd larva instars were attacked by a hymenopterans endoparasitoid Dolichogenidea trachalus (Nixon, 1965) (Lepidoptera: Braconidae). Rate of parasitism ranged from 5.6 to 85% in two regions (Aleppo and Idleb) under field conditions. The biological studies revealed that the female parasitoid D. trachalus (Nixon) deposited a single egg internally in the young host larva of Palpia unionalis Hubner. The full-grown parasitoid larva emerged from the fourth instar host larva for pupation. The duration of the life cycle rang! ed from 10 to 15 days, under an average laboratory temperature 25 [degree]C and 65% RH. The incubation- and the larval period ranged from 5 to 9 days, and the pupal period from 4 to 6 days at 25 [degree]C and 65% RH. The adult longevity of both sexes ranged from 8.6 to 15.8 days at 15[long dash]30 [degree]C and 60[long dash]70% RH. The sex ratio (female: male) was approximately 1:0.8 under laboratory conditions. Percentage of parasitism differed greatly within any given year, among years, and localities. It may be concluded that this parasitoid, among other factors, did play a role in the regulation of its host population density. Insecta (Arthropoda): Predator; Araneae (Arachnida): Predator; Hymenoptera (Insecta): Parasite; Dolichogenidea trachalus (Braconidae): Parasite; Palpita unionalis (Pyralidae): Host, Prey. Araneae, Insecta: Insect prey, Palpita unionalis (Lepidoptera), Predator prey list, predation impact, predator prey record, Cultivated land habitat, Olive grove, Syria; Dolichogenidea trachalus: Egg laying, Oviposition, host parasite relationships, prevalence, Life cycle and development, Lepidopteran hosts, Palpita unionalis, Population sex ratio, Cultivated land habitat, Olive grove, Humidity, Temperature, Syria; Hymenoptera: Lepidopteran hosts, Palpita unionalis, Host parasite list, prevalence, Cultivated land habitat, Olive grove, Syria; Palpita unionalis: Hymenopteran parasites, Host parasite list, prevalence, Dolichogenidea trachalus, Host parasite relationships, parasitoid biology, Microbial diseases, Population regulation, predator prey list, predation impact, predator prey record, Arachnid predators, Araneae, Insect predators, Cultivated land habitat, Olive grove, Syria. Arachnids; Arthropods; Chelicerates; Hymenopterans; Insects; Invertebrates; Lepidopterans. none