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

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

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 aime...

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Bibliographic Details
Main Authors: Diouneia Lisiane Berlitz, Aline Oliboni de Azambuja, Alessandra Sebben, Jaime Vargas de Oliveira, Lidia Mariana Fiuza
Format: Article
Language:English
Published: Instituto de Tecnologia do Paraná (Tecpar) 2012-10-01
Series:Brazilian Archives of Biology and Technology
Subjects:
Alternative pest control
entomopathogenic bacteria
insecticidal activity
botanical insecticidal
Online Access:http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132012000500012
Description
Summary: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.
ISSN:1516-8913
1678-4324

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