Encarsia formosa Gahan is used worldwide for commercial control of whiteflies in greenhouse crops. Commercial use began in Europe in the 1920s, but by 1945 interest waned due to the development of pesticides. After 1970, use was reinitiated and has expanded from 100 hectares of greenhouse crops to 4800 hectares in 1993 (van Lenteren and Woets, 1988; Hoddle et al., 1998).
Comparison of the greenhouse area in various parts of the world with the area employing biological control agents shows that most usage of E. formosa occurs in Europe and Russia and that the largest concentrations of greenhouse production in which E. formosa is not extensively used are in North America and Asia, particularly Japan (Hoddle et al. 1998). These are areas where increased use of E. formosa would be possible.
Encarsia formosa was originally described from specimens reared from an unidentified aleyrodid on geranium (Pelargonium sp.) in 1924 in a greenhouse in Idaho (USA) (Gahan 1924). There are no