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The antibiosis effect of gallic acid on Spodoptera litura F. (Lepidoptera: Noctuidae) and its parasitoid evaluated by feeding six days old larvae on artificial diet incorporated with different concentrations (5 ppm, 25 ppm, 125 ppm, 625 ppm, 3125 ppm) of the phenolic compound revealed higher concentration (LC50) of gallic acid had a negative impact on the survival and physiology of S. litura and its parasitoid Bracon hebetor (Say) (Hymenoptera:Braconidae). The mortality of S. litura larvae was increased whereas adult emergence declined with increasing concentration of gallic acid. The developmental period was delayed significantly and all the nutritional indices were reduced significantly with increase in concentration. Higher concentration (LC50) of gallic acid adversely affected egg hatching, larval mortality, adult emergence and total development period of B. hebetor. At lower concentration (LC30) the effect on B. hebetor adults and larvae was non-significant with respect to control. Gene expression for the enzymes viz., Superoxide dismutase, Glutathione peroxidase, Peroxidase, Esterases and Glutathione S transferases increased while the total hemocyte count of S. litura larvae decreased with treatment. Our findings suggest that gallic acid even at lower concentration (LC30) can impair the growth of S. litura larvae without causing any significant harm to its parasitoid B. hebetor and has immense potential to be used as biopesticides.

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In an endeavour to explore secondary metabolites as an important and safe means of pest management, we investigated the effects of pyrogallol, a phenolic compound, on the growth and development of Spodoptera litura (Fab.). It is a serious pest of a large number of economically important crops. Different concentrations viz., 1, 5, 25, 125, 625, 3125 ppm of pyrogallol were incorporated in artificial diet of larvae and the antibiosis influence was ascertained by feeding second instar larvae on this diet. The larval and total development period increased significantly with increase in concentration of the pyrogallol. Inhibitory effects of the compound were observed on per cent pupation, per cent emergence and adult longevity. All nutritional indices were also significantly affected. Thus it can be considered as a promising substance to be used as a biopesticide against the insect pest.