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.

Encapsulation of Rosmarinus officinalis essential oil and of its main components in cyclodextrin: application to the control of the date moth Ectomyelois ceratoniae (Pyralidae).

BACKGROUND: Synthetic insecticides are the most useful tools for preventing losses caused by insect pest's infestation during storage. However, the use of pesticides should be limited because of the development of insect resistance and their adverse effects on human health and environment. In the last decades, natural insecticidal products, principally essential oils (EOs) and their active components, exhibited potential alternatives for pest control. Nevertheless, due to their volatile nature, encapsulation could be considered as the most appropriate solution. Therefore, this work aims to investigate the fumigant ability of inclusion complexes of Rosmarinus officinalis EO and its major constituents (1,8-cineole, α-pinene and camphor) with 2-hydroxypropyl-beta-cyclodextrin (HP-ß-CD) against Ectomyelois ceratoniae (Pyralidae) larvae. RESULTS: The encapsulation within HP-ß-CD reduced greatly the release rate of the encapsulated molecules. Therefore, free compounds were more toxic than those encapsulated. Moreover, results revealed that encapsulated volatiles exhibited interesting insecticidal toxicity towards E. ceratoniae larvae. In fact, after 30 days mortality rates were 53.85, 94.23, 3.85 and 42.31% for α-pinene, 1,8-cineole, camphor and EO, respectively, encapsulated within HP-ß-CD. In addition, results showed also that 1,8-cineole free and encapsulated was more effective toward E. ceratoniae larvae than the other tested volatiles. Additionally, the HP-ß-CD/volatiles complexes exhibited best persistence compared to the volatiles components. The half-life of the encapsulated α-pinene, 1,8-cineole, camphor and EO (7.83, 8.75, 6.87 and 11.20 days) was significantly longer than that of the free ones (3.46, 5.02, 3.38 and 5.58 days). CONCLUSION: These results sustain the utility of R. officinalis EO and its main components encapsulated in CDs as treatment to stored-date commodities. © 2023 Society of Chemical Industry.

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.

Laurel essential oil: biological activities and application for semolina preservation against the red flour beetle Tribolium castaneum (Tenebrionidae).

The phytochemical composition of Laurus nobilis essential oil and their anticholinesterase, antioxidant, and insecticidal potential were studied. Also, the oil volatile fraction was compared in semolina at the beginning and after storage periods. For that, a headspace solid-phase-microextraction analysis (HS-SPME) coupled with gas chromatography and mass spectrometry was undertaken. Significant quantitative and qualitative differences of the oil volatile fraction were detected according to storage periods and occupation space ratios. Additionally, anti-acetylcholinesterase activity of L. nobilis oil against T. castaneum adults was evaluated. Results revealed that insecticide activity varied according to storage duration and occupation space. Besides, the oil acts on acetylcholine hydrolysis by inhibiting the activity of acetylcholinesterase. These results highlighted that L. nobilis essential oil may be recommended as an eco-friendly alternative for preserving semolina during storage.

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.

In Vitro Potential of Clary Sage and Coriander Essential Oils as Crop Protection and Post-Harvest Decay Control Products.

Owing to their various application fields and biological properties, natural products and essential oils (EO) in particular are nowadays attracting more attention as alternative methods to control plant pathogens and pests, weeds, and for post-harvest applications. Additionally, to overcome EO stability issues and low persistence of effects, EO encapsulation in ß-cyclodextrin (ß-CD) could represent a promising avenue. Thus, in this work, the EO distilled from two aromatic plants (Salvia sclarea L. and Coriandrum sativum L.) have been evaluated in vitro for their antifungal, herbicidal and insecticidal activities, against major plant pathogens and pests of agronomical importance. Both plants were grown on unpolluted and trace-element-polluted soils, so as to investigate the effect of the soil pollution on the EO compositions and biological effects. These EO are rich in oxygenated monoterpenes (clary sage and coriander seeds EO), or aliphatic aldehydes (coriander aerial parts EO), and were unaltered by the soil pollution. The tested EO successfully inhibited the growth of two phytopathogenic fungi, Zymoseptoria tritici and Fusarium culmorum, displaying IC50 ranging from 0.46 to 2.08 g L-1, while also exerting anti-germinative, herbicidal, repellent and fumigant effects. However, no improvement of the EO biological effects was observed in the presence of ß-CD, under these in vitro experimental conditions. Among the tested EO, the one from aerial parts of coriander displayed the most significant antifungal and herbicidal effects, while the three of them exerted valuable broad-range insecticidal effects. As a whole, these findings suggest that EO produced on polluted areas can be of great interest to the agricultural area, given their faithful chemical compositions and valuable biological effects.

The mitogenome of the true bug Nysius cymoides (Insecta, Heteroptera) and the phylogeny of Lygaeoidea.

The complete mitochondrial genome of the true bug (Homoptera) Nysius cymoides (Spinola, 1837) is herein described and used for phylogenetic comparison with other species of Lygaeoidea. The mtDNA has a gene order and other molecular features typically observed in hexapods, and a long A + T-rich region, due to the occurrence of several repeat units. The phylogenetic analyses support the monophyly of all families except Rhyparochromidae.

Cryptic Diversity Hidden within the Leafminer Genus Liriomyza (Diptera: Agromyzidae).

Leafminer insects of the genus Liriomyza are small flies whose larvae feed on the internal tissue of some of the most important crop plants for the human diet. Several of these pest species are highly uniform from the morphological point of view, meaning molecular data represents the only reliable taxonomic tool useful to define cryptic boundaries. In this study, both mitochondrial and nuclear molecular markers have been applied to investigate the population genetics of some Tunisian populations of the polyphagous species Liriomyza cicerina, one of the most important pest of chickpea cultivars in the whole Mediterranean region. Molecular data have been collected on larvae isolated from chickpea, faba bean, and lentil leaves, and used for population genetics, phylogenetics, and species delimitation analyses. Results point toward high differentiation levels between specimens collected on the three different legume crops, which, according to the species delimitation methods, are also sufficient to define incipient species differentiation and cryptic species occurrence, apparently tied up with host choice. Genetic data have also been applied for a phylogenetic comparison among Liriomyza species, further confirming their decisive role in the systematic studies of the genus.