Mortality of Oryzophagus oryzae (Costa Lima, 1936) (Coleoptera: Curculionidae) and Spodoptera frugiperda (J E Smith, 1797) (Lepidoptera: Noctuidae) Larvae Exposed to Bacillus thuringiensis and Extracts of Melia azedarach
Braz. arch. biol. technol
;
55(5): 725-731, Sept.-Oct. 2012. ilus, tab
Artigo
em Inglês
| LILACS
| ID: lil-651656
ABSTRACT
Oryzophagus oryzae (Costa Lima 1936) (Coleoptera Curculionidae) and Spodoptera frugiperda (J E Smith, 1797) (Lepidoptera Noctuidae) cause important crop losses in southern Brazil. Control is possible by the use of the bacteria Bacillus thuringiensis and extracts of Melia azedarach. This study aimed to evaluate the mortality, in vivo, of O. oryzae and S. frugiperda submitted to two isolates of B. thuringiensis and the aqueous extract of M. azedarach. The LC50 for O. oryzae due to bacteria was 5.40μg/mL (Bt 2014-2) and due to plant extract 0.90μg/mL. For S. frugiperda, the Bt 1958-2 bacterial suspension (1.10(10)UFC/mL) caused a 100% of corrected mortality, showing that the purified Cry proteins caused a CL10 of 268μg/mL five days after the treatments, and M. azedarach toxins caused a CL50 173μg/mL four days after the treatment. Corrected mortality for O. oryzae and S. frugiperda in the interaction between the bacterial and plant toxins were 11 and 6%, respectively. In the PCR analysis of B. thuringiensis isolates, DNA fragments were enlarged and corresponded to the cry1 and cry2 genes for Bt 1958-2. Thus, it could be concluded that the usage of Bt 2014-2 active against O. oryzae larvae; Bt 1958-2 for S. frugiperda and, for both the insect species, M. azedarach aqueous extract could be used.
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DisponíveL
Índice:
LILACS (Américas)
Idioma:
Inglês
Revista:
Braz. arch. biol. technol
Assunto da revista:
Biologia
Ano de publicação:
2012
Tipo de documento:
Artigo
País de afiliação:
Brasil
Instituição/País de afiliação:
Universidade Vale do Rio dos Sinos/BR
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