Production of low cost <i>Bacillus thuringiensis</i> based-biopesticide for management of chickpea pod-borer <i>Helicoverpa armigera</i> (Huebn) in Pakistan

Abstract

The biopesticide was prepared from locally available low cost ingredients: dried beef blood, molasses and mineral salts (ZnCl 2 , MgCl 2 , MnCl 2 , CaCl 2 CaCl 2 , and FeCl 3 ) which were used as medium for the laboratory scale production of B acillus thuringiensis ( B.t .) bio-pesticide by shake flask technique. Indigenous B.t. isolate PA-Sb- 46.3 which produced two crystals—bi-pyramidal and cuboidal was found 73.6 times toxic against H. armigera than reference strain Bacillus thuringiensis var. kurstaki (HD-I-S-1980) used. Medium was fermented for 72 hours at 30℃ ± 2℃ and 160 rpm. 72 h fermented medium showed 95% - 99% sprulation, with spore yield of 3.97 × 10 9 spores/ml, and LC 50 value to 1 st instar larvae of H. armigera was 0.53 μg/ml diet. Preservatives and diluents used in the biopesticide were found to be effective to store at room temperature over a period of 30 months. These observations suggested that the biopesticide produced was effective and highly economical for the industrial scale production to manage H. armigera in Pakistan.