Bacillus thuringiensis survey in Brazil: geographical distribution and insecticidal activity against Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

Abstract

Levantamento de Bacillus thuringiensis no Brasil: Distribuição Geográfica e Atividade Inseticida ContraSpodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)RESUMO -O total de 3408 cepas de Bacillus thuringiensis foi isolado de 1448 amostras de solo provenientes de 10 estados, em quatro regiões brasileiras, abrangendo 96 municípios. As cepas foram avaliadas contra lagartas de Spodoptera frugiperda (J. E. Smith) sendo que apenas 62% mataram entre 81% e 100%, e 1758 não causaram mortalidade. O Sul destacou-se com 16,6% de cepas eficientes (mortalidade>75%) do total obtido por região, seguido das regiões Centro Oeste (3,1%), Sudeste (1,1%), e Nordeste (0,4%). PALAVRAS-CHAVE: Insecta, bactéria, isolado nativo, controle biológico, patologiaABSTRACT -A total of 3408 strains of Bacillus thuringiensis were collected from 1448 soil samples in 10 Brazilian states, four different geographical regions, covering 96 counties. These strains were evaluated against Spodoptera frugiperda (J.E. Smith) larvae. Only 62% killed between 81% and 100% and 1758 caused no mortality. Highest proportion of efficient strains (larval mortality above 75%) was found from the total isolated per region in the South Region (16.6%), followed by Western Central (3.1%), Southeast (1.1%) and Northeast Region (0.4%).

Isolation of Bacillus thuringiensis strains that contain Dipteran-specific cry genes from Ilha Bela (São Paulo, Brazil) soil samples

“…In all of the soil samples that were collected in this study, bacterial growth was detected with an average of 2.53 B. thuringiensis isolates/sample, which corresponds with the averages of 3.45, 2.35 and 1.91 B. thuringiensis isolates/ sample that were previously described by Polanczyk et al (2003), Valicente and Barreto (2003), and Barreto (2005), respectively. Because the isolates were initially characterized from the soil samples by morphological features, we sequenced the 16S ribosomal subunit genes of the isolates to confirm that they were B. thuringiensis.…”

Molecular characterization of Bacillus thuringiensis using rep-PCR

“…B. thuringiensis can be found in different substrates such as soil, water, plant surfaces, dead insects, grain dust, spider webs and stored grain (Glare & O’Callaghan 2000; Valicente & Barreto 2003; and Miralles & Peres 2004). This bacterium also shows a high genetic variability and is widely distributed in nature (Vilas-Boas et al 2002).…”

Molecular Characterization of Bacillus thuringiensis cyt Genes and Their Effect Against Fall Armyworm, Spodoptera frugiperda

“…The isolates containing cyt genes identified in this study showed different levels of toxicity against S. frugiperda (Valicente et al, 2000;Valicente & Barreto, 2003;Valicente & Fonseca, 2004;Valicente et al, 2010). Two isolates caused 100% mortality (isolates 1646JAB and 1656JAB) and one caused 79% of larval mortality (strain 1168C).…”

“…These isolates expressed different toxicities against S. frugiperda larvae (Valicente & Barreto, 2003). In addition, Bt var.…”