Lethal activity of two Bacillus thuringiensis strains against Haemonchus contortus histotropic larvae.
The in vitro lethal activity of two Bacillus thuringiensis strains (IB-16 and IB-61) against Haemonchus contortus histotropic fourth stage larvae (L(4)) was evaluated. Each B. thuringiensis strain was used as soluble proteins at different concentrations. In addition, the in vitro lethal dose (LD(50)) of each strain was determined against H. contortus L(4) at different times. Data were analyzed by ANOVA and Tukey tests. Less than 50% mortality was observed at 50 and 100 microg/mL during all bioassays. More than 50% mortality was observed at 200 microg/mL at 3 and 5 days after interaction with IB-16 and IB-61, respectively. A 100% mortality was observed with IB-16 on day 5. The LD(50) with IB-16 was 248 microg/mL on day 3, and IB-61 showed an LD(50) at 227 microg/mL on the day 5. Both toxins may have potential as biocontrol agents.
Hernández Linares
Ismael
I
Centro Nacional de Investigación Disciplinaria en Parasitologia Veterinaria, Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias, México.
López Arellano
María Eugenia
ME
Mendoza de Gives
Pedro
P
Liébano Hernández
Enrique
E
de la Parra
Alejandra Bravo
AB
D000818:Animals; D001413:Bacillus thuringiensis / Q000472:pathogenicity*; D006189:Haemonchus / Q000254:growth & development*; D007814:Larva / Q000254:growth & development*; D007928:Lethal Dose 50