The combination of destruxin a with insecticide chlorantraniliprole increases virulence against Plutella xylostella L.

Diamondback moth,plutella xylostella,is a major worldwide pest of cruciferous vegetables and has developed high levels of resistance against many pesticides. the current research presents the joint action of destruxin a and chlorantraniliprole against resistant strain of plutella xylostella were bioassayed under laboratory and field cage conditions. an apparent increase in adjusted larval mortality in a dose-dependent manner was observed when destruxin a and chlorantraniliprole were applied individually. the level of synergism between destruxin a and chlorantriniliprole was affected by the concentration of each component in the mixtures. the synergistic effects were observed in treatments (80.0+3.0),(40.0+1.0),(40.0+3.0) and (80.0+1.0),respectively. the treatments (40.0+3.0) and (80.0+0.3) were determined as additive effects according to their cumulative adjusted mortalities,me and chi-square values. in field cage experiments synergistic action was observed for 80.0+3.0 treatment with its cumulative mortality values of 69.93/87.05/98.87% at 48,72 and 96 h post-treatment while additive effects were observed for treatments (40.0+0.3),(40.0+1.0) and (80.0+0.3). copyright 2016 zoological society of pakistan.