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Abstract Encapsulation of essential oils (EOs) is an important strategy that can be applied to intensify the stability and efficiency of these compounds in integrated pest management. The present study aimed to investigate the sub-lethal activity of polymer-based EOs nanoparticles against red flour beetle, Tribolium castaneum adults as an important critical pest of stored products. Chitosan nanoparticles (CSNPs) containing garlic and cinnamon essential oils (GEO and CEO) prepared using the ionic cross-link technique. Stability of nano-formulations evaluated over temperature and storage time. The fumigant effect (LC10, LC20, LC30) and contact toxicity (LC10, LC15, LC25) determined. In addition, the contact toxicities of EOs and their nanoparticles on nutritional indices evaluated. An olfactometer used to assess the repellent activity of EOs and EOs loaded in CSNPs (EOs@CSNPs) in sub-lethal fumigant concentrations. Characterization results showed GEO loaded in CSNPs has particle size of 231.14 ± 7.55 nm, polydispersity index (PDI) value of 0.15 ± 0.02, encapsulation efficiency (EE) percentage of 76.77 ± 0.20 and zeta potential of − 18.82 ± 0.90 mV, in which these values for the CEO loaded in CSNPs (CEO@CSNPs) changed to 303.46 ± 0.00 nm, 0.20 ± 0.05, 86.81 ± 0.00% and − 20.16 ± 0.35 mV, respectively. A lower PDI value for both CSNPs showed an appropriate NPs size distribution. Furthermore, NPs size and encapsulation efficiency did not change in various temperatures and during four months which confirm good stability of the EOs@CSNPs. In LC30 of GEO@CSNPs, the maximum repellency was determined as 66.66 ± 3.33. Among nutritional indices, in LC25 of GEO@CSNPs, the relative growth rate (RGR) (0.011 ± 0.003 mg.mg−1.day−1), relative consumption rate (RCR) (0.075 ± 0.004 mg.mg−1.day−1) and feeding deterrence index (FDI) (54.662 ± 1.616%) were more affected, so GEO@CSNPs was more effective than CEO@CSNPs. The results of repellent and anti-dietary activities of EOs and EOs@CSNPs confirmed the higher repellency and adverse effectivity on nutritional indices of Tribolium castaneum pest treated with EOs@CSNPs compared to free EOs. In conclusion, the NPs form of GEO and CEO can be a novel and efficient carrier for improving the repellent and anti-nutritional activities of EOs.

During sampling on species diversity of arthropods associated with ash trees in Mashhad and vicinity, a number of specimens of parasitoids from Eulophidae were collected in May 2013. They were identified by Dr. Lütfiye Gençer (Cumhuriyet University of Turkey) as: Aprostocetus catius (Walker, 1839), Chrysocharis pubicornis (Zetterstedt, 1838), Neochrysocharis chlorogaster (Erdös, 1966), Asecodes erxias (Walker, 1848). These species were reported for the first time from Iran. Eulophidae is the largest family in the Chalcidoidea including over 3900 species, 540 genera and four subfamilies including Euderinae, Eulophinae, Entedoninae, Tetrastichinae. So far, 106 species belonging to 37 genera in four subfamilies (Entedoninae, Euderina, Eulophinae, Tetrastichinae) from Iran have been recorded.