Potential of two populations of Amblyseius swirskii (Acari: Phytoseiidae) for the control of Bemisia tabaci biotype B (Hemiptera: Aleyrodidae) in Brazil.

Predatory mites of the family Phytoseiidae are commercialized in European and North American countries for the control of whiteflies (Insecta: Aleyrodidae). Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) is one of the predators used for that purpose. This predator is not found in Brazil and in many other countries, but its introduction could promote biological control of Bemisia tabaci (Gennadius) biotype B (silverleaf whitefly) in those countries. The aim of this study was to compare two populations of A. swirskii as predators of eggs of B. tabaci of two different ages, as well as the acceptance of those populations for other food types [eggs of Tetranychus urticae Koch; larvae and protonymphs of Aleuroglyphus ovatus (Troupeau) (Astigmatina: Acaridae) and cattail pollen (Typha domingensis Persoon)]. One of the populations of A. swirskii was collected in the Republic of Benin, in tropical Africa, and the other was commercially available in The Netherlands. The comparison was done to evaluate the population with better potential for practical use, and to determine food types that could be used for mass rearing the predator. Experiments were conducted at 28 ± 1 °C, 80 ± 10 % relative humidity and 12 h photophase. Both populations were able to oviposit when fed eggs of B. tabaci, but the Netherlands population showed higher oviposition rate (2.3 and 1.6 times higher on young and older eggs, respectively). Higher predation rates were observed for eggs up to 24 h of age in comparison with older eggs. Aleuroglyphus ovatus proved to be a promising prey for possible mass rearing of this predator in Brazil, where that astigmatic mite is found naturally when pollen was used as food, no significant difference was observed for oviposition rate between populations. The results suggested a higher potential of the Netherlands population of A. swirskii for the control of B. tabaci biotype B in this country for augmentative biological control, with the possible use of A. ovatus as food for the mass production and pollen of T. domingensis as a food supplement for this predator in practical field releases.