Norape argyrrhorea, Hubner (Lep.:Megalopygidae), is becoming the most importantdefoliator for oil-palm plantations in Peru(South America). Apart from direct damage,feeding of the larvae also causes wounds thatprovide sites for entry for a complex ofphytopathogenic fungi. Chemical control of N. argyrrhorea is costly and results in theparallel reduction of the populations ofseveral predator and parasitoid insect speciesthat previously limited proliferation of thispest. For this reason, alternative controlmethods are being investigated. Apreviously undescribed occluded virus has beenfound responsible for fast and massivemortality among wild populations of the pest.Based on morphology, protein analysis andnucleic acids, this virus named NoarCPV,belongs to the family Reoviridae. Results ofthe first applications of NoarCPV in anoil-palm plantation demonstrated rapidmortality to population densities below damagethresholds.