Biochemical characterization of spiromesifen and spirotetramat as lipid synthesis inhibitors on cotton leaf worm, Spodoptera littoralis

Abstract

The obtained results showed that both compounds were moderately toxic against the second instar larvae of S. littoralis. The mortality percentages caused by the field rate of spiromesifen and spirotetramat were 51.7 and 60.0%, respectively. The lethal concentrations for 50% of tested insect population (LC50) were 170.1 and 42.2 ppm, respectively. The total lipid content was determined in treated larvae and compared with the untreated. The percentage of total lipid in spiromesifen- and spirotetramat-treated larvae was 2.17 and 2.21%, respectively, compared with 2.42% in untreated larvae. GC/MS also was used in identification of fatty acids composition of S. littoralis larvae.