Effect of Manihot esculenta (Crantz) leaf extracts on antioxidant and immune system of Spodoptera litura (Lepidoptera: Noctuidae)

Abstract Nowadays, the use of chemical insecticides has led to development of resistance in insects, and causing harmful effect to non-target organisms and environment. Plant-mediated biopesticides are an alternative source for the management of insect pests. Present study focuses on lethal and sublethal effects of Manihot esculenta on immune response and antioxidant enzyme activity of Spodoptera litura larvae. The result shows that high toxicity of petroleum benzene leaf extract in S. litura larvae with LC50 of 109.89 mg/mL. FT-IR analysis of leaf extracts shows the presence of alkane, alkyl halides, misc, amines, esters and carboxylic acid. GC-MS analysis of extracts contains 10 compounds, notable among them are 9, 12-Octadecadienoic acid (10.93) and Lupeol (11.35), 4, 4, 6A, 6B, 8A, 11, 14 B-Octamethyl- (37.41). In addition, several sublethal effects of the leaf extract were also observed. There was a significant increase in the total haemocyte count and differential haemocyte count in S. litura larvae. Phenoloxidase (PO) levels, detoxification enzymes such as CytP450, GST and catalase levels were significantly increased, whereas, SOD levels were lower than the non-treated S. litura larvae. Manihot esculenta leaf extracts is an alternative to chemical insecticides for the management of S. litura larvae and may be used for the management of other agricultural insect pests.