Electronic Journal of Biotechnology
versión On-line ISSN 0717-3458
FONTANA CAPALBO, Deise Maria; VALICENTE, Fernando Hercule; OLIVEIRA MORAES, Iracema de y PELIZER, Lúcia Helena. Solid-state fermentation of Bacillus thuringiensis tolworthi to control fall armyworm in maize. Electron. J. Biotechnol. [online]. 2001, vol.4, n.2, pp. 9-10. ISSN 0717-3458.
The well-known entomopathogenic bacterium Bacillus thuringiensis (Bt) produces a spore-crystal complex which is responsible for its biocide characteristic, and the bacterium can be obtained by fermentation, either in liquid or semi-solid substrates. This paper presents a successful way to achieve solid-state fermentation of active Bt var. tolworthi (Btt) against Spodoptera frugiperda (fall armyworm) in corn. More than 109 CFU/g were obtained using humidified rice as substrate maintained in polypropylene bags. This active complex (substrate plus spore-crystal of Bt) was prepared in order to obtain 2 x 106 spores/mL; the final suspension then sprayed via tractor on corn fields. On the treated plants, mortality of neonate larvae was 100% within two days of spraying, and all larvae were found dead on leaves. During one maize crop cycle, two applications were made, and up until 70 days after emergence it was not necessary to apply any other insecticide for fall armyworm control.
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