The parasite then develops inside the whietfly scale, and midway through the development of Encarsia within the whitefly, the scale turns dark. It becomes black for greenhouse whitefly, and transparent brown for sweet potato whitefly. This occurs after 10 days at normal greenhouse temperatures. Another 10 days is required before adults emerge. Adult Encarsia emerge from the parasitized scale by chewing a hole in the top of the scale.
Adults also kill whitefly scales by direct feeding.
Otherwise, they feed on honeydew secreted by the whiteflies. Adults can live for 30 days but normally are active for about 10 days. The complete life cycle requires nearly 28 days in commercial greenhouses. Encarsia are sold as black parasitized scales that have been fixed onto cards. Each card contains 150 developeing parasites.