none Enter The intensive use of chemical control in horticulture induces disorders in the trophic chain, obstructing the activity of benefic insects. Natural vegetation neighbouring crop plots influence phytofagous insects and their natural enemies. Effective natural control is achieved mainly in the bordering lines. The objective of this work was to know if Baccharis dracunculifolia (Compositae, Astereas) is a natural host of aphids and their natural enemies from Fall up to Spring. Phytophagous and entomophagous insect populations were followed, identified and quantified in the INTA Monte Vera experimental, field (31[degree] 30[minute] 14[second] S Lat., 60[degree] 43[minute] 32[second] W Long). Sistematic samples were taken on three sampling areas, based upon the vegetation surrounding the host plants. Aphis gossipii (Homoptera, Aphididae) was found with a maximun of 1740 individuals in one of the areas. The most important entomophagous were Lysiphlebus testaceipes (Hymenoptera, Aphidiidae) and in less amounts, Chiysopidae (Neuroptera) and Syrphidae (Diptera), which change according to the study area, the temperature and the pressence of flowers. Among the predators, the Coleoptera: Cycloneda sanguinea, Scymnus argentinicus and Scymnus sp., Eriopis connexa, Corinus coeruleus and 011a abdominalis were the most abundant, aduts and inmature stages. Numerical and reproductive responses were observed in the predators. It was concluded that B. dracunculifolia was an important host of aphids and their natural enemies. This plant species may influence the horticultural crops, through the regulation of insects populations and the reduction of chemical control. Insecta (Arthropoda): [Predator]. Aphis gossipii (Aphidoidea): [Host, Parasite, Prey]. Lysiphlebus testaceipes (Aphidiidae): [Parasite]. noneEmail20150402 csalto@rafaela.inta.gov.ar email failed