Toxicological, biological and biochemical effects of two nanocomposites on cotton leaf worm, Spodoptera littoralis (Boisduval, 1833)

Abstract

Cotton leaf worm, Spodoptera littoralis (Boisduval, 1833), is one of the most dangerous pests in Egypt, causing economically significant losses of different crops. The present study was aimed to evaluate toxicological, biological and biochemical effects of two nanocomposites, Silver (Ag) and graphene oxide (GO) nanomaterials over magnesium chlorophillin (Mg-Chl/Ag and Mg-Chl/GO) at three concentrations (1, 10, 100 ml/L) against 2nd instar larvae of S. littoralis. The results showed that larval mortality rate was positively correlated with the increase of concentrations of the tested nanocomposites and time after exposure. The mortality rate in nanographene oxide composite were higher than nano silver. LC50 (lethal concentration of 50% of a group of test larvae) values were 10.27 and 16.14 mg/L at Mg-Chl/Ag and Mg-Chl/GO compound at 2 h exposure to light. Some biological aspects of S. littoralis resulted from the treated 2nd instars larvae with two nanocomposites were recorded. Larval, pupal durations, pupation, adult emergence rate and pupal weight were significantly lower in all concentrations compared to untreated larvae. All tested samples showed decrease in total carbohydrates, total proteins and total lipids. Obtained results suggest that using silver and graphene oxide nanomaterials over the magnesium chlorophillin would be a useful component for controlling S. littoralis.