Eco-friendly management strategies of insect pests: long-term performance of rosemary essential oil encapsulated into chitosan and gum Arabic.

This study focused on encapsulation of Rosmarinus officinalis essential oil (EO) on chitosan and gum Arabic matrix in various ratios and with varying essential oil concentrations. Additionally, UV/VIS spectroscopy was used to determine cumulative-release profiles. The insecticidal activity was tested against Tribolium castaneum and Oryzaephilus surinamensis, both pests of stored products. In terms of encapsulation efficiency (EE%) and loading capacity (LC%), capsules had EE at 45.8% and LC at 2.31%. Furthermore, many minor compounds were lost after encapsulation, until identifying only 1,8-cineole, α-terpineol, and camphor after 60 d of storage. The fumigant tests demonstrated that encapsulated EO exhibited an effective control against insect pest during storage periods, namely, 30, 45, and 60 d with 99, 66, and 46% mortality for T. castaneum and 100, 84, 82% mortality for O. surinamensis.

The Maize Caterpillar Mythimna (= Leucania) loreyi (Duponchel, 1827) (Lepidoptera: Noctuidae): Identification, Distribution, Population Density and Damage in Tunisia.

Surveys were conducted during 2020 and 2021 to study the emerging lepidopteran pests inflicting cereals in Tunisia, with specific emphasis on maize and sorghum crops. A species was collected from traps placed in the Jendouba, Bizerte, Nabeul and Gabes regions. Thus, this study carried out first report on its identification, distribution, population density and damage. Results showed that M. loreyi was abundant in all prospected areas, with total adult captures reaching 4779 and 9499 moths on sorghum and maize, respectively, during 2020. Moreover, the mean infestation percentage reached its maximum during August at 31.05% and 20.69% for the Jendouba and Bizerte regions, respectively, while the highest infestations were observed in the Gabes and Nabeul regions during July, with respective mean values of 13.54% and 21.35%. In addition, results revealed that the highest pest incidence occurred in the Gabes region, with values of 11.1 ± 0.47 and 5.7 ± 0.48 during 2020 and 2021, respectively. Additionally, results pointed out that M. loreyi achieved two summer generations in the different localities of Tunisia. Overall, this study provides basic insights into the ecology and population biology of M. loreyi, which are required to establish an effective pest control program.

Insights for the control of dried-fruit beetle Carpophilus hemipterus (Nitidulidae) using rosemary essential oil loaded in chitosan nanoparticles.

Natural insecticidal products, essentially essential oils and their bioactive compounds are available as an excellent alternative method to control insect pests as well as they are less toxic to human health. However, due to their volatile constituents, encapsulation could be considered as the most suitable solution for their practical application. Therefore, this study aims to explore the insecticidal toxicity of chitosan nanoparticles loaded with Rosmarinus officinalis essential oil against adults of Carpophilus hemipterus. Chitosan nanoparticles were prepared by ionic gelation method with an encapsulation efficiency 41.543.1% and loading capacity 5.24G0.28%. Results revealed that chitosan nanoparticles loaded rosemary oil exhibited interesting insecticidal toxicity towards C. hemipterus adults in stored dates with 50.73% mortality. Overall, this work pointed out that the innovative design method based on chitosan-nanoparticles loaded rosemary oil can be promoted in integrated pest management program for stored date pests.

Screening for insecticidal toxicity of Urginea maritima (L.) bulbs and Asphodelus microcarpus (L.) tubers for the control of Tribolium castaneum (Tenebrionidae).

This research was conducted to determine the effect of geographical distribution on morphological characteristics of plants and some chemical compounds such as polyphenols. Moreover, we explore the contact toxicity of ethanolic and methanolic extracts from Urginea maritima bulbs and Asphodelus microcarpus tubers collected from three localities in the North West of Tunisia against Tribolium castaneum adults. The toxicity results demonstrated that both of the studied plant extracts had an effective control against T. castaneum at concentration 7.5 µL/L air, thus total mortality reached. In addition, results showed plant extracts with methanol exhibited high mortality percentage of T. castaneum. On the other hand, results revealed that chemical composition of U. maritime bulbs and A. microcarpus tuber extract depends on the soil components and geographical distribution of plants. The present investigation confirmed that A. microcarpus and U. maritima may be recommended as an eco-friendly alternative to synthetic insecticide against T. castaneum.