Bioefficacy and Molecular characterization of Native Bacillus thuringiesis (Berliner) Isolates Against Lepidopteran Pests of Cabbage
Loading...
Date
2011
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
UAS, Dharwad
Abstract
The bio-efficacy of one hundred native Bacillus thuringiensis isolates was
assessed against five day old lepidopteran insects (Spodoptera litura Fab.,
Crocidolomia binotalis Z. and Plutella xylostella L.). Molecular characterization and
crude protein assay of eleven efficient isolates was done to identify the presence of
insecticidal genes and the efficacy to target insects respectively. Based on the
bioefficacy and the presence of the cry genes, consortia were developed against P.
xylostella. Out of the 100 isolates tested Tx-232 and 531/a recorded cent per cent
mortality against P. xylostella, 90 per cent mortality was shown by Tx-379 and 86.67
per cent mortality by Tx-201, AIM-72(1) and AIM-72 (2). Among isolates, Tx-201,
Tx-29, Tx-379, AIM-72(2) showed 86.67 per cent and AIM-72(1), Tx-202 showed
80.00 per cent mortality against C. binotalis. Tx-232 registered 73.33 per cent and Tx-
202 recorded 66.67 per cent mortality of S. litura larvae. Out of eleven native Bt
isolates tested for lepidopteran specific cry genes, cry1 gene was amplified in six
isolates, cry2 amplified in four isolates, cry8 and cry9 was amplified in two isolates.
However cry20 was not present in any of the eleven isolates. All the selected eleven
isolates performed well against P. xylostella, C. binotalis but not against S. litura in
crude protein assay. The consortium of two [531/a + Tx 232 and 531/a + AIM-72(2)]
isolates recorded cent per cent mortality, three isolates combinations [Tx 379 + 531/a
+ Tx 232 and 531/a + Tx 232 + AIM-72(2) and four isolates combination [531/a + Tx
232 + AIM-72(2) + Tx 379] showed cent per cent mortality with quicker knock down
effect against P. xylostella compared to the reference.
Description
Keywords
Agricultural Entomology