The present Research Thesis named "Chemical control of Tagosodes orizico/us (Muir) on rice crop (Oryza Zativa), capirona variety, on Cacatachi District", was developed on the second campaign of 1999 in the field belonging to the National University of San Martín, Cacatachi District, Province of San Martin (Bajo Mayo Valley). The place is distinguished by a humid tropical climate with annual average precipitations of 1 1 OOmm, temperatures fluctuating between annual maximum 37 ºC and minimum 22 ºC and with an annual relative humidity of 65 % at 350 msl. and clay soils. The aim of the present work was to evaluate the control of T. orizicolus using 4 pesticides (lmidaclprid, Fenthion, Cipermetrina and Monocrotofos) on different concentrations and the effect of the application on the beneficia! fauna, with emphasis on predators. 8 treatments were applied with 4 repetitions with a complete...