Two parasites, Eretmocerus eremicus and Encarsia formosa for whitefly control

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Both Eretmocerus eremicus and Encarsia formosa are tiny parasitic wasps that are mainly parasitic to whiteflies. These wasps are generally sold as parasitized pupae that can be easily released in the field for the control of whiteflies. Eretmocerus eremicus act as both external and internal parasite whereas Encarsia formosa act as only internal parasite.

Facts (show all)

- Effective against the following whitefly species
  • The banded winged whitefly, Trialeurodes abuttnea
  • The Greenhouse whitefly, Trialeurods vaporarium
  • The silver leaf whitefly, Bemicia argentifolii
  • The sweet potato whitefly, Bemicia tabaci
+ Key factors for Eretmocerus eremicus and Encarsia formosa effectiveness
  • Both Eretmocerus eremicus and Encarsia formosa wasps are mainly parasitic to whiteflies.
  • Eretmocerus eremicus wasps are yellowish and brownish in color whereas Encarsia formosa are black in color.
  • Both Eretmocerus eremicus and Encarsia formosa wasps are generally sold as parasitized pupae that can be easily released in the field for the control of whiteflies
+ How parasitic Eretmocerus eremicus and Encarsia formosa wasps work in the field
  1. When parasitic Eretmocerus eremicus wasps released either in the fields or greenhouses, their females lay eggs underneath the immature stages (nymphs) of whiteflies that is in between the leaf surface and the nymphs whereas females of Encarsia formosa lay eggs inside the nymphs.
  2. Depending on the temperature, hatching of eggs of both wasps takes place within 4 days.
  3. The larvae of Eretmocerus eremicus develop as both external and internal parasite whereas larvae of Encarsia formosa develop as only internal parasite.
  4. As an external parasite, these young wasp larvae of Eretmocerus eremicus generally attach to the underside the nymph’s body with the hook-like mouth parts. Then they enter into nymph’s body by chewing a small hole and become as an internal parasite. In contrast, the eggs of Encarsia formosa hatch into larvae only inside the whitefly nymph.
  5. Once inside the whitefly nymph, Eretmocerus eremicus wasp larvae become and remain dormant until whitefly nymphs form pupae but larvae of Encarsia formosa continue feeding until whitefly nymph or pupae dies.
  6. Once pupae are formed, Eretmocerus eremicus wasp larvae then become active and begin releasing digestive enzymes that helps to liquefy body content of whitefly pupa.
  7. Then the Eretmocerus eremicus wasp larvae start feeding on the liquefied body content and eventually kill the pupae of whiteflies.
  8. While feeding inside the whitefly pupae or nymphs, larvae of both Eretmocerus eremicus and Encarsia formosa develop through three developmental stages (instars) for 12-15 days and emerge as adults.
  9. These emerged adult wasps mate and females start laying eggs as stated above and life cycle continues.
+ Which stages of whitefly are parasitized by parasitic wasps Eretmocerus eremicus and Encarsia formosa?
  • whitefly nymphs
  • Pupae of whiteflies
+ How many Eretmocerus eremicus or Encarsia formosa wasps should be released?
  • Both Eretmocerus eremicus and Encarsia formosa wasps are commercially available as mixed parasitized whitefly pupae.
  • It is recommended to release three Eretmocerus eremicus parasitized whitefly pupae per plant infested with whiteflies every week for 4 weeks.
  • It is recommended to release 10-15 Encarsia formosa parasitized whitefly pupae per 10 sq m garden area infested with whiteflies 3-4 times weekly.
+ When Eretmocerus eremicus wasps should be released for the effective control of whiteflies?
  • Both the parasitic wasps should be released when there is a presence of whiteflies on the plants.
  • Release them early in the morning or evening when day light level and temperature low.
  • Release these wasps against whiteflies when temperature is between 25 and 30°C.
+ How Eretmocerus eremicus and Encarsia formosa wasps should be released for effective control of whiteflies?
  • Release these wasps within 18 hours of receipt but if you are not ready to release them then store them at cool place (at 45-50°F).
  • When you receive product in bottles, make sure that the pupae are evenly distributed in the carrier material.
  • In order to do this, lay bottle on its side and rotate it so that material will be mixed evenly.
  • Open the bottle in whitefly infested area and sprinkle the carrier material and wasp pupae onto the leaves, on the surface of growing media or in the pots.
  • If you receive product in the blisters, open the blisters and hang on the leaf petiole or branches in a shaded area where wasps will emerge from these blisters and look for appropriate place to lay eggs.
+ Why you need them
  • they can reduce the crop damage by feeding on pupae of whiteflies
  • they can parasitize young larvae whiteflies
  • they are able to actively search for their host nymphs (larvae), parasitize them and feed on their pupae
  • they can reproduce and continue their life cycle in the garden after first application
  • they are commercially available and easy to release in the greenhouses or fields
+ Why they are safer than traditional pesticides
  • they do not damage plants
  • do not cause any harm to the personnel involved in their production and application
  • food products are safe to handle and eat when they are treated with wasps
  • they do not harm humans, animals and pollute the environment
+ Research Papers
  1. Bellamy, D.E., Asplen, M.K. and Byrne, D.N. 2004. Impact of Eretmocerus eremicus (Hymenoptera : Aphelinidae) on open-field Bemisia tabaci (Hemiptera : Aleyrodidae) populations. Biological Control 29: 227-234.
  2. Berndt, O. and Meyhofer, R. 2008. Whitefly control in cut gerbera: is it possible to control Trialeurodes vaporariorum with Encarsia formosa? Biocontrol 53: 751-762.
  3. Hoddle, M.S., Sanderson, J.P. and Van Driesche, R.G. 1999. Biological control of Bemisia argentifolii (Hemiptera : Aleyrodidae) on poinsettia with inundative releases of Eretmocerus eremicus (Hymenoptera : Aphelinidae): does varying the weekly release rate affect control? Bulletin of Entomological Research 89: 41-51.
  4. Hoelmer, K.A. 2007. Field cage evaluation of introduced Eretmocerus species (Hymenoptera : Aphelinidae) against Bemisia tabaci strain B (Homoptera : Aleyrodidae) on cantaloupe. Biological Control 43: 156-162.
  5. van Lenteren, J.C., van Roermund, H.J.W. and Sütterlin, S. 1996. Biological control of greenhouse whitefly (Trialeurodes vaporariorum) with the parasitoid Encarsia formosa:How does it work? Biological Control 6: 1–10.

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