Effect of plant secondary metabolites on common cutworm, Spodoptera litura (Lepidoptera: Noctuidae)

The effect of various flavonoids, lectins and phenyl beta-(D)-glucoside on larval survival, weights and the activities of digestive (total serine protease and trypsin) and detoxifying (esterase and glutathione-S-transferase) enzymes of Spodoptera litura larvae at 7days after treatment was studied through diet incorporation assay. Flavonoids (rutin, chlorogenic acid, quinic acid, caffeic acid, naringenin, quercitin, kaempferol, myricetin, catechin, and ferulic acid) were incorporated in artificial diet at 100, 500 and 1000ppm, lectins: groundnut leaf lectin (GLL), concavalin A (ConA) and phenyl beta-(D)-glucoside at 1, 2 and 5 mu g/mL. Flavonoids such as rutin, quercitin and kaempferol at 1000ppm were more toxic to S. litura larvae than quinic acid, caffeic acid, naringenin, myricetin, catechin, and ferulic acid. Larval growth and development were significantly reduced in S. litura larvae fed on a diet with GLL and ConA at 5 mu g/mL compared to the larvae fed at 2 and 1 mu g/mL concentrations. The larvae fed on flavonoid-treated diets showed significant reduction in serine protease, trypsin and esterase activities. The flavonoids such as rutin, chlorogenic acid, quinic acid, naringenin, quercitin, kaempferol and myricetin, and lectins, GLL and ConA can be utilized in insect control programs.