Abstract: A formulation prepared by microencapsulation of nucleopolyhedrovirus SfMNPV 003occlusion bodies (OBs) with a methacrylic acid polymer was assessed on maize plants infestedwith Spodoptera frugiperda under mesh house conditions. No obvious differences in the level ofinsect plant damage were observed between plants treated with formulated and unformulatedvirus. On days 7 and 11, values of damages ranged from 2.5 to 17.5% for plants treated withvirus, while in control plants damages varied between 90 to 70%. Formulated and unformulatedvirus at a rate dose of 1×107 OBs/ml (750g/ha) efficiently reduced insect damage under semicontrolled conditions. Biopesticide was also evaluated under field conditions in a maize crop, byusing three doses. Biological and chemical products reduced similarly the insect plant damage.The results obtained allowed to recommend treatments at a biopesticide dose of 750g/haequivalent to 7.5×1011 OBs/Ha for controlling S. frugiperda under field conditions in maize cropswith applications when fresh damage reaches 15%.