Abstract

                                The present study aimed to investigate the toxicity and synergistic effect ofbinary mixtures containing chlorantraniliprole and sesame oil at differentratios against second and third instar larvae of fall armyworm(FAW), Spodoptera frugiperda. The toxicity of different concentrations (LC25and LC50) of chlorantraniliprole with or without sesame oil (1, 2.5 and 5 percent) on second and third instar larvae of FAW was determined using theleaf discdip bioassay method. A combination of chlorantraniliprole LC50plus sesame oil 2.5 per cent has resulted in 74.42 and 81.81 per centlarval mortality on the second and third instars larvae of FAW, respectively.The mortality percentage was 1.52 and 1.57 fold higher than the singleeffect for the second and third instars of FAW, respectively. These resultsshowed that this combination exhibited high potentiating synergism in boththe instars of FAW larvae under laboratory conditions. The activity ofCarboxyl Esterase (CarE), Mixed Function Oxidase (MFO) and Glutathione-STransferase (GST) were found to be lesser in chlorantraniliprole LC50 plussesame oil 2.5 per cent combinations than in single toxicity treatments.Therefore, sesame oil showed good synergism with chlorantraniliprole atthe ratio of chlorantraniliprole LC50 plus sesame oil 2.5 per cent on fallarmyworm under laboratory conditions.

Key words : Chlorantraniliprole; Detoxifying enzymes; Fall armyworm; Maize; Sesame oil; Synergist