1.- To determine the incidence of L. bonariensis in L. perenne grasslands of different aged and phenological stages in different agroecological zones of regions de La Araucanía, Los Ríos and Los Lagos 2.- To select endophyte strains present in cultivars introduced and collected populations of L. perenne that present a high bioinsecticide activity on L. bonariensis, H. elegans, P. herrmanni and D. pallens, under laboratory conditions 3.- To determine the controlling effect of the selected cultivars of L. perenne with endophyte fungus on the root feeding larval instars of hypogeous pest such as H. elegans, P. herrmanni and D. pallens, under field conditions 4.- To determine the controlling effect of the selected cultivars of L. perenne with endophyte fungus on both larvae and adults of the epigean insect L. bonariensis, under field conditions.