RESUMO
Generalist predators have the potential advantage to control more than one pest and to be more persistent than specialist predators because they can survive on different foods. Moreover, their population growth rate may be elevated when offered a mixture of prey species. We studied a generalist predatory mite Balaustium sp. that shows promise for biological control of thrips and whiteflies in protected rose cultures in Colombia. Although starting its life in the soil, this predator makes excursions onto plants where it feeds on various arthropods. We quantified life history parameters of the predator, offering high densities of three pest species: first-instar larvae of Frankliniella occidentalis, eggs of Trialeurodes vaporariorum and Tetranychus urticae, either alone or in combination. The predators completed their life cycle on each diet. The egg-to-egg period was c. 2 months. All eggs were laid in one batch in 1-2 days, indicating a pronounced semelparous reproduction pattern. In general, females reproduced earlier and laid more eggs on mixed diets, and these early reproducers consequently had higher population growth rates than late reproducers. The best diet in terms of egg-to-egg period and juvenile survival was the combination of eggs from whiteflies and spider mites. Spider mite eggs alone and western flower thrips larvae alone were the worst diets. It remains to be investigated whether mixed diets promote the population growth rate of Balaustium sufficiently for biocontrol of whiteflies and thrips in the presence of alternative prey, such as spider mites, to become effective.
Assuntos
Dieta , Ácaros/crescimento & desenvolvimento , Controle Biológico de Vetores , Animais , Feminino , Cadeia Alimentar , Hemípteros , Reprodução , TisanópterosRESUMO
El ácaro depredador Phytoseiulus persimilis ha sido usado con éxito para el control del ácaro fitófago Tetranychus urticae, el cual constituye una de las plagas mas importantes en los cultivos de rosa de la Sabana de Bogotá. En Colombia esta estrategia de control se ha visto limitada por la falta de disponibilidad de los depredadores en el comercio del producto. En el presente trabajo se proponen criterios para estandarizar las bases para la producción de P. persimilis en plantas de frijol infestadas con poblaciones de T. urticae de diferentes tiempos de desarrollo, utilizando una proporción constante de depredadores liberados. Se encontró que plantas infestadas con poblaciones de T. urticae por más de tres semanas permiten obtener mayores incrementos de población de los depredadores y que aproximadamente a los 25 días después de realizada la liberación, de los depredadores en las plantas infestadas, se obtienen los mayores poblaciones del depredador en estado de ninfa y adulto para cosechar y usar como estrategia de control en los cultivos.
The predatory mite Phytoseiulus persimilis has been used successfully to control the phytophagous mite Tetranychus urticae in rose crops, in what is one of the most important pests. In Colombia , this control strategy has been limited by the lack of predators in the trade of the product. Here was proposed to standardize the basis for the production of P. persimilis on bean plants infested with populations of T. urticae of different development times, using a constant proportion of predators released. We found that populations of plants infested with T. urticae for more than three weeks resulted in higher population increase of predators and at approximately 25 days after the release of predators on plants infested, you get the largest predator populations in a state of nymph and adult to harvest and use as a strategy control in crops.
