Bio-efficacy and physiological effects of Eucalyptus globulus and Allium sativum essential oils against Ephestia kuehniella Zeller (Lepidoptera: Pyralidae)

Abstract

Toxicity Allium sativum and Eucalyptus globulus essential oils were investigated against Ephestia kuehniella larvae in addition to physiological effects on digestive enzymes, intermediary metabolism, antioxidant response and storage macromolecules. The LC50s of 2.801 and 6.111 µl/ml were recorded for A. sativum- and E. globulus EOs as the highest concentrations caused 83.3% and 80% of larval mortality. The lowest activities of α-amylase, TAG-lipase, and carboxypeptidase were recorded in the larvae treated by A. sativum EO, while the larvae treated by E. globulus EO showed the lowest activities of trypsin, chymotrypsin, and aminopeptidase. The activities of elastase and glucosidases decreased in the treated larvae but no significant differences were recorded between EOs. Activities of esterase and glutathione S-transferase significantly increased in the larvae treated by EOs similar to aminotransferases while the activities of lactate dehydrogenase, acid- and alkaline phosphatases significantly decreased in the EO-treated larvae. The higher activities of ascorbate peroxidase, glycerol-6-phosphate dehydrogenase, malondialdehyde, and ratio of RSSR/RSH were found in the EO-treated larvae while superoxide dismutase, peroxidase, and catalase had the highest activities in EgEO-treated larvae. Both EOs significantly decreased the activity of acetylcholine esterase and the amounts of storage macromolecules, protein, glycogen, and triglyceride.