How to Manage Pests:
Pest Management and Identification
Scientific name: Encarsia formosa
DESCRIPTION Life Cycle
Encarsia formosa, an endoparasitic wasp, is the most important parasite of the greenhouse whitefly. Adult female Encarsia formosa are tiny wasps (<1 mm in length) with a dark brown to black head and thorax and a bright yellow abdomen. Males are dark in color, but are rare. Adult females host feed on all immature stages by puncturing the body with their ovipositors and consuming the exuding blood. Eggs are laid into third and fourth-instar whiteflies and hatch into larvae that feed within the whitefly nymph and grow through three larval instars before killing the host. Greenhouse whitefly nymphs turn dark brown or black approximately one week after being parasitized and their skin forms a black pupal case for the parasite. Silverleaf whiteflies parasitized by E. formosa stay lighter in color and do not turn black. Like many whitefly parasites, E. formosa leaves a circular hole and black feces in the host remains. In contrast, emerging whiteflies leave a ragged or T-shaped emergence hole in their mostly clear or whitish pupal skin.
E. formosa is used for whitefly control in greenhouses on tomatoes, strawberries and in floricultural and nursery plants. Biological control of the greenhouse whitefly can often be provided in enclosed areas by introducing sufficient numbers of commercially available E. formosa. Release programs of Encarsia formosa are most effective when the initial population of whiteflies is quite low (only a few whiteflies per plant) and long-residual insecticides have not been applied in advance of the parasite release. For biological control to be successful use more selective and less persistent insecticides, and control ants since they disrupt the oviposition of E. formosa.