Evaluation of Bacillus vallismortis (Bacillales: Bacillaceae) R2 as insecticidal agent against polyphagous pest Spodoptera litura (Lepidoptera: Noctuidae)

The insecticidal potential of cells and acid-precipitated biomolecules (APB) of Bacillus vallismortis (Roberts) (Bacillales: Bacillaceae) R2 was evaluated against polyphagous pest Spodoptera litura. The intact cells of isolate R2 and its APB preparation significantly increased larval mortality. Both cells and APB significantly delayed the development and reduced adult emergence of S. litura. The toxicity of isolate R2 was evident from the emergence of morphologically deformed adults with crumpled and underdeveloped wings. The nutritional physiology of larvae fed on APB-supplemented diet was also adversely affected resulting in significant reduction of relative growth and consumption rate as well as efficiency of conversion of ingested and digested food. Thus, the intact viable cells and APB of B. vallismortis R2 may serve as environmental-friendly alternatives to chemical insecticides.