Selection of entomopathogenic fungi to control Bemisia tabaci biotype B | Sele?ao de fungos entomopatogenicos para o controle de Bemisia tabaci bi?tipo B

5 ilus. 3 tab. 29 ref.Se evalu? la actividad patog?nica de cepas de Beauveria bassiana (25), Metarhizium anisopliae (7), Paecilomyces spp. (11) y Verticillium lecanii (1) en el control de Bemisia tabaci biotipo B. Los experimentos fueron realizados en condiciones controladas (25 m?s menos 0,5 ?C, 80 m?s menos 5 porciento HR y 12:12 L:D). Se utilizaron hojas de soya infestadas con ninfas de tercer instar, inoculadas con 2 mL de la suspensi?n (10 exponente 7 conidios/mL), aplicada por medio de una torre de Potter (15 lb pol 2). Todas las cepas fueron patog?nicas para las ninfas, causando entre 10 y 89 porciento de mortalidad. Sin embargo, las cepas 447 y 969 (B. bassiana), 1037, 816 y E9 (M. anisopliae), y CB144 (Paecilomyces spp.) alcanzaron 57, 59, 61, 89 y 48 porciento de mortalidad, respectivamente. Fue posible concluir que los aislamientos E9, 1037 y 816 de M. anisopliae y las cepas 447 y 969 de B. bassiana constituyen opciones promisorias para el control microbiano de ninfas de mosca blanca biotipo B. Isolates of Beauveria bassiana (25), Metarhizium anisopliae (7), Paecilomyces spp. (11), and Verticillium lecanii (1) were evaluated for their pathogenicity against third instar nymphs of Bemisia tabaci biotype B. The experiment was conducted under controlled conditions (25 more less 0,5 ?C, 80 more less 5 percent RH and 12:12 L:D). Soybean leaves were treated with 2 mL of conidial suspentions (10 exponent 7 conidia/mL), applied thrugh a Potter Tower (15 lb/pol 2). All the isolates were pathogenic to nymphs and caused from 10 to 89 percent of mortality. The most pathogenic isolates were B. bassiana 447 and 969, M. anisopliae 1037, 816 and E9, and Paecilomyces spp. CB144, causing 57, 59, 61, 68, 89 and 48 percent of mortality, respectively. Results indicate that M. anisopliae isolates E9, 1037 and 816, and B. bassiana isolates 447 and 969 are the most promising for the development of bioinsecticides to control silverleaf whitefly nymphs

"Andean" and "non-Andean" ITS-2 and mtCytB haplotypes of Triatoma infestans are observed in the Gran Chaco (Bolivia) : population genetics and the origin of reinfestation

In Bolivia, the Gran Chaco ecoregion suffers from serious problems of house reinfestation with Triatoma infestans despite vector control by insecticides spraying. In order to identify the origin of the triatomines collected after spraying, the genetic structure of T. infestans populations collected in four neighboring villages, before and after spraying, was analyzed using ITS-2 and mtCytB sequencing. Before spraying, only the mtCytB marker detected genetic differentiation among the 4 populations. After spraying, the mtCytB analysis of the populations from two of the studied villages supported the hypothesis in favor of a local origin for the triatomines in each village. Surprisingly, ITS-2 and mtCytB haplotypes previously found only in Andean areas were also present with high frequencies in the studied populations; these domestic populations of the Gran Chaco seem to be the result of a mixture of "Andean" and "non-Andean" triatomines probably generated by the human passive transport of triatomines from the Andes to the Gran Chaco

"Andean" and "non-Andean" ITS-2 and mtCytB haplotypes of Triatoma infestans are observed in the Gran Chaco (Bolivia) : population genetics and the origin of reinfestation

International audienceIn Bolivia, the Gran Chaco ecoregion suffers from serious problems of house reinfestation with Triatoma infestans despite vector control by insecticides spraying. In order to identify the origin of the triatomines collected after spraying, the genetic structure of T. infestans populations collected in four neighboring villages, before and after spraying, was analyzed using ITS-2 and mtCytB sequencing. Before spraying, only the mtCytB marker detected genetic differentiation among the 4 populations. After spraying, the mtCytB analysis of the populations from two of the studied villages supported the hypothesis in favor of a local origin for the triatomines in each village. Surprisingly, ITS-2 and mtCytB haplotypes previously found only in Andean areas were also present with high frequencies in the studied populations; these domestic populations of the Gran Chaco seem to be the result of a mixture of "Andean" and "non-Andean" triatomines probably generated by the human passive transport of triatomines from the Andes to the Gran Chaco

New insights on the Chagas disease main vector Triatoma infestans (Reduviidae, Triatominae) brought by the genetic analysis of Bolivian sylvatic populations

Triatoma infestans is the main and most widespread vector of Chagas disease in South America. For the first time, a large sample of sylvatic populations of T. infestans was analyzed by ITS-2 and mtCytB sequencing. ITS-2 showed a low level of polymorphism but revealed a dichotomy between the Andean and non-Andean sylvatic populations. On the contrary, mtCytB sequences showed a high polymorphism (19 haplotypes determined by 35 variable sites) revealing a strong structuring between most of the sylvatic populations and possible ancient isolation and bottleneck in the Northern Andes. The dichotomy Andean vs. non-Andean populations was not observed with this marker. Moreover, mtCytB haplotype genealogies showed that the non-Andean haplotypes would have derived from the Andean ones, supporting somewhat an Andean origin of the species. Nevertheless, a non-Andean origin could not be discarded because a remarkable genetic diversity was found in the non-Andean sample. The comparison of the sylvatic haplotypes with the domestic ones from GenBank suggested multiple events of T. infestans domestication in Andean and non-Andean areas, instead of a major and unique domestication event in the Bolivian Andes, as previously proposed

New insights on the Chagas disease main vector Triatoma infestans (Reduviidae, Triatominae) brought by the genetic analysis of Bolivian sylvatic populations

International audienceTriatoma infestans is the main and most widespread vector of Chagas disease in South America. For the first time, a large sample of sylvatic populations of T. infestans was analyzed by ITS-2 and mtCytB sequencing. ITS-2 showed a low level of polymorphism but revealed a dichotomy between the Andean and non-Andean sylvatic populations. On the contrary, mtCytB sequences showed a high polymorphism (19 haplotypes determined by 35 variable sites) revealing a strong structuring between most of the sylvatic populations and possible ancient isolation and bottleneck in the Northern Andes. The dichotomy Andean vs. non-Andean populations was not observed with this marker. Moreover, mtCytB haplotype genealogies showed that the non-Andean haplotypes would have derived from the Andean ones, supporting somewhat an Andean origin of the species. Nevertheless, a non-Andean origin could not be discarded because a remarkable genetic diversity was found in the non-Andean sample. The comparison of the sylvatic haplotypes with the domestic ones from GenBank suggested multiple events of T. infestans domestication in Andean and non-Andean areas, instead of a major and unique domestication event in the Bolivian Andes, as previously proposed

Susceptibility and resistance to deltamethrin of wild and domestic populations of Triatoma infestans (Reduviidae: Triatominae) in Bolivia: new discoveries

Bolivia is a high-endemic country for Chagas disease, for which the principal vector is Triatoma infestans (Triatominae). This is a mainly domestic species that is also found in the wild environment. Recently, an increasing number of studies have shown the importance of Triatominae resistance to insecticides, especially in Bolivia. Data regarding the susceptibility/resistance of wild and domestic populations of T. infestans to deltamethrin are presented. For the first time, domestic populations of the department of Santa Cruz were tested, showing low resistance. Although most of the wild populations were found to be susceptible to deltamethrin, three populations from three departments showed a mortality rate of less than 100%. This result is emphasised here