Journal of Veterinary Parasitology

An in vitro experiment was conducted to evaluate the efficacy of five different types of bacteria belonging to the genus Bacillus and one toxin against Rhipicephalus microplus, tropical cattle tick. The bacterial bio-control agents (BBCAs) tested were Bacillus thuringiensis var. israelensis, B. weihenstephanensis var. WSBC, B. weihenstephanensis var. KBAB4, and B. sphaericus. Bacillus thuringiensis var. kurstaki and its toxin (Dipel 2x, 17600 IU per mg) procured from market, were also used. These bacteria were found effective in causing mortality in adult ticks; however, their lethal effect was observed significantly on the tick eggs. The LC values observed after evaluation were 3.5×10⁵ and 3.8×10⁷; 5.0×10⁹ and 4.7×10⁶; 2.2×10⁷ and 5.6×10⁵; 2.8×10⁵ and 2.0×10⁴; 80080 IU and 55440 IU; 135520 IU and 17.430 IU, respectively for B. thuringiensis var. israelensis, B. weihenstephanensis var. (WSBC), B. weihenstephanensis var. (KBAB4), B. sphaericus, B. thuringiensis var. kurstaki, B. thuringiensis var. kurstaki (toxin) against the adult and egg stages of R. microplus. Additionally, significant reduction in egg laying capacity of female ticks and reduced hatching of eggs treated with BBCAs were observed. In view of lack of any earlier record traced through literature search, this is the first report from India wherein BBCAs were evaluated for tick control of livestock.