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. A strip of 10 cards contains 1,500 Encarsia whitefly parasites. It is important to hang the cards from lower leaves in the shade, and avoid wetting them while watering.
Double rates are necessary for the sweet potato whitefly.
For greenhouse cucumbers use 1 Encarsia per 2 plants BI weekly.