Evolution of the larvicidal effects of secondary metabolites produced by Bacillus subtilis (Ehrenberg, 1835) Cohn, 1872 wild type UTB1 and mutant M419 against Plutella xylostella (L., 1758) (Lep.: Plutellidae)

The effects of Bacillus subtilis, wild type bacterium UTB1 and mutant M419, on two larval instar groups of the diamondback moth, Plutella xylostella L. (Lep.: Plutellidae) until three days after treatment have been investigated. Larval mortality rate increased with increasing the concentration and over the days after treatment. Increasing the larval instar resulted in elevating the LC50 value for both types of biosurfactants. In terms of lethality, there was no significant difference between the two bacteria in the final mortality rate after three days.