Effect of dihydrodillapiole on pyrethroid resistance associated esterase inhibition in an Indian population of Spodoptera litura (Fabricius)

• Published in: Pesticide biochemistry and physiology 2012, Vol.102 (1), p.86-90
• Main Authors: Shankarganesh, K, Walia, Suresh, Dhingra, Swaran, Subrahmanyam, B, Ramesh Babu, S
• Format: Article
• Language: English
• Subjects: acetates; Biological and medical sciences; cyhalothrin; cypermethrin; Dihydrodillapiole; Esterase; esterases; Fundamental and applied biological sciences. Psychology; glutathione transferase; Insecticide synergist; insects; instars; larvae; Phytopathology. Animal pests. Plant and forest protection; pretreatment; Protozoa. Invertebrates; Spodoptera litura; synergism; synergists; toxicity
• ISSN: 0048-3575; 1095-9939
• DOI: 10.1016/j.pestbp.2011.11.001

Resistance in Spodoptera litura (Fabricius) has been attributed to enhanced detoxification of insecticides by increased levels of esterases, oxidases and/or glutathione S-transferases. Enzyme inhibiting insecticide synergists can be employed to counter increased levels of such enzymes in S. litura. Dihydrodillapiole induced synergism of pyrethroid toxicity was examined in the laboratory-reared third instar larval population of S. litura collected in Delhi (susceptible), and Guntur (resistant) region of Andhra Pradesh, India. The Guntur population was found to be 7.04 and 10.19 times resistant to cypermethrin and lambdacyhalothrin, respectively. The activity of cypermethrin, lambdacyhalothrin and profenophos against susceptible and resistance populations of S. litura, was gradually increased when used along with a plant-derived insecticide synergist dihydrodillapiole. The α-naphthyl acetate hydrolysable esterase activity in Delhi population was less as compared to the Guntur population. Resistance associated esterases in Delhi population were inhibited by pre-treatment with dihydrodillapiole. The esterase level in insect was instantly reduced initially, sustained for about 3h and equilibrated at 4h post treatment. The esterase activity of Guntur population was increased to 1.28μmoles/mg/min at 2h post treatment and subsequently reduced to lower than 0.70μmoles at 4–12h post treatment. The variation in esterase activity is suggestive of its homeostatic regulation in test populations. Dihydrodillapiole thus caused significant reduction of resistance in S. litura to cypermethrin, lambda cyhalothrin and profenophos.