Coniferous trees constitute a major part of Isfahan landscape trees. Aphids are one of the growth limiting factors of these trees. Aphids affect trees by feeding plant sap, excreting honeydew and impregnating foliage cause absorption of dusts on plant, reducing photosynthesis and falling down the leaves trees. In this study, coniferous aphids were collected on Pinus . The most abundant aphid species on pine trees in Isfahan was Eulachnus tuberculostemmatus (Hem., Lachnidae). Seasonal population changes of this species was studied in Isfahan by weekly sampling in two consecutive years. Some important population growth and fecundity parameters of the aphid were measured in the field conditions using leaf cage and life table constructions at Summer and Autumn. In addition, effects of drought stre at three levels (without, moderate and severe stress) and temperature at four levels (15, 20, 25 and 30 0 C) on growth and population parameters were studied at greenhouse and laboratory conditions, respectively. The aphid natural enemies were also collected and identified using weekly sampling results of seasonal fluctuations studies showed that the aphid has two population peaks in Spring and Autumn. Spring peak was in early April and population decreased at the end of June, and in summer population was very low. In Autumn, because of cooler weather the population increased, so that another peak was observed in November. In Winter the population was very low but overwintering females was found. Based on the results, the aphid is heterocyclic e. i. no eggs were detected. Based on the result of life tables, intrinsic rate of increase (r m ), net reproductive rate (R 0 ), gross reproductive rate (GRR), mean generation time (T), mean nymphal period, mean longevity of adult female and mean number of nymph to adult female was higher in autumn than in summer. The highest and lowest r m was recorded in 25 and 15 0 C, respectively. Drought stress had a significant effect on some parameters of the aphid population, so that the lowest nymphal period, highest rate reproduction, longevity of adult female, R 0 and GRR were observed in severe drought stress. Four Coccinellidae speacies Adalia bipunctata L, Hippodamia variegata (Goeze), Propylea quatuordecimpunctata L and Coccinella septempunctata L and one lacewing speacies were identification as the aphid ’ s natural enemies. The population peaks of these natural enemies were coincides with the aphid. The results of this study could be applied for better management of pine aphids in the future. Key words: Fertility life table, Pine trees, Intrinsic rate of increase, Pine aphid