In this study, the toxicity of three concentrations 2, 4 and 6 % of three natural essential oils: Garlic
(Allium sativum: Alliaceae) , Neem (Azadirachta indica: Meliaceae) and Jojoba (Simmondsia chinensis:
Simmondsiaceae) against the fourth instar larvae of the greater wax worm, Galleria mellonella L. (Lepidoptera :
Pyralidae ) were evaluated as well as the mortality percentages were computed. Mortality percentages were high
at Garlic oil treatments, followed by neem and Jojoba compared to control. In addition, the values of LC50 were
1.983, 2.842 and 3.958% for Garlic, Neem and Jojoba essential oils, respectively. Regarding enzyme activites
was Lactate Dehydrogenase activity (LDH), Glutathione S-Transferase (GST), ATPase, acetyl cholinesterase
and Alpha esterase’s were measured in the 4th instar larvae treated with the forementioned essential oils. The
results indicated an increase in the LDH activity in all treatments compared with control. Also increase in the
activity of GST and Alpha esterase’s activity were recorded after treatment with jojoba and Garlic oils and
decrease after treatment with Neem. Also, the results showed a decrease in ATPase activity after treatment
with Neem and Jojoba oils and increase after treatment with Garlic oils. Results revealed decrease in the activity
of acetylcholinesterase enzymes in all treatments. The garlic oil come first followed by neem oil and jojoba
come last.