A search was made in California (USA) for alternative parasites able to control the greenhouse whitefly T. vaporariorum (Westw.) on tomatoes in greenhouses with a low temperature regime.
The preselection of candidate species for biological control by means of laboratory methods is discussed. Four aphelinid species (Encarsia formosa Gahan, E. pergandiella Howard, E. sp. near meritoria Gahan and Eretmocerus sp.) could be reared and a laboratory method was developed to test their parasitization efficiency at 17 ± 1°C constant temperature: the reproductive capacity of the four species was measured over a period of 20 days.
The possible consequences of the different reproductive strategies of these last two species for their use as biological control agents are discussed. No definite answer to the question which of these two species would be most suitable for whitefly control under low temperature conditions could be given, therefore greenhouse experiments have been initiated in the Netherlands and the U.K.