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The wax moth is one of the honeybee pests that cause a lot of damage and loss for the beekeepers in Tunisia. The use of insecticides is more and more used although they are known to contaminate wax and honey. This study aims to test the essential oils of two North African common plants Thymbra capitata L. and Mentha pulegium L. efficacy as alternative method by fumigation on instars of Galleria mellonela L. We also determined the duration of the development stages of the great wax moth (GWM) presented in Tunisia. Results showed that under a temperature ranged between 30 and 33°C, the total duration from eggs to adults of GWM lasted 51 days. The fumigant test showed the toxicity of both oils on larvae instars tested. The second larvae instar was more susceptible than the 4th instar. Moreover, M. pulegium was more toxic against the 2nd larvae instar than T. capitata with an LC50 at 48h of 41.82 and 456.27 µl/L air, respectively. The essential oils present a good alternative to the insecticides to control wax moths.

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Encapsulation of Rosmarinus officinalis essential oil (EO) on chitosan and gum Arabic matrix were prepared at different ratios with various concentrations of essential oil. The capsules were characterized by their encapsulation efficacy (EE%) and loading capacity (LC%). The cumulative release profiles were evaluated by UV/Vis spectroscopy. The chemical compounds for free and encapsulated essential oil were determined by GC-MS technique and the insecticidal toxicity against Tribolium castaneum and Oryzeaphilus surrinamensis was determined by fumigant bioassays. Results showed that capsules with ratio chitosan: gum arabic: EO (1: 1: 0.5) revealed the highest EE (45.8%) and LC (2.31%). In vitro release profiles demonstrated that encapsulated essential oil showed a sustained release especially for the ratio with high EO concentration. The major constituents of the rosemary essential oil were 1,8-cineole (39.67%), Camphor (18.04%), followed by borneol (10.52%) and α-Pinene (6.33%). After encapsulation numerous minor compounds have been missing during storage periods until identifying only 1, 8-cineole, α-terpineol and camphor after 60 days of storage. The fumigant tests demonstrated that encapsulated EO exhibited an effective control against insect pest during storage periods namely 30, 45, 60 days with 99%, 66%, 46% for T. castaneum and 100%, 84%, 82% for O. surrinamensis. This work supports the hypothesis that major essential oil components were responsible for its pesticidal activities over storage. Besides, toxicities against T. castaneum and O. surinamensis adults was mainly attributed to 1, 8-cineole.