The essential oil from industrial hemp (Cannabis sativa L.) by-products as an effective tool for insect pest management in organic crops

Benelli G., Pavela R.

The control of insect pests and vectors is a timely challenge for public health. The prevention of bites from bloodsucking insect species is based to a large extent on the use of chemical repellents and pesticides. However, their effectiveness is currently endangered, due to the fast-growing resistance levels in the targeted vectors, besides their negative impact on human health and the environment. Therefore, natural product research has been claimed as a helpful tool to develop effective green pesticides and repellents. Among them, essential oils (EOs) extracted from plants received peculiar attention for applications in “the real world”, since they showed high efficacy, multiple mechanisms of action and low toxicity on non-target vertebrates. However, the large majority of research items published on the topic studied the potential of EOs in the fight against mosquitoes (668 research items) and ticks (155), while only a relatively limited amount (

Benelli G., Pavela R.

Ticks act as vectors of a wide range of infectious agents, far encompassing any other group of bloodsucking arthropods worldwide. The prevention of tick-borne diseases is strictly linked to the successful management of tick vector populations. The employ of repellents can represent a worth solution to avoid tick bites. It is widely adopted to protect travellers and pets exposed to ticks during limited periods of the year. The use of natural products as active ingredients in eco-friendly repellent formulations is currently a prominent research area, due to the wide diversity and high effectiveness of a number of plant-borne compounds, with special reference to essential oils (EOs) extracted from medicinal and aromatic species. Here, we reviewed current knowledge available on EOs tested as repellents against tick species of veterinary importance. Furthermore, we analysed the effectiveness of pure compounds isolated from EOs as tick repellents and their potential implications for practical use in the öreal world". A quantitative analysis of literature available is this research field was provided, along with its impact (i.e., in terms of citations over time) on the scientific community of researchers in tick control science and natural product chemistry. In the final sections, future outlooks are highlighted. We discussed major challenges to stabilize the most effective EOs and pure molecules, explore the synergistic and antagonistic effects in blends of EOs and/or pure constituents, standardize currently adopted testing methods, and evaluate non-target risks of herbal repellents.

Pavela R.

Aphids are an important agricultural pest that not only damage plants by suction, but can also transmit a number of economically important plant viruses. Protection against aphids is based on the use of synthetic insecticides. However, these products can be dangerous for non-target organisms. Therefore, it is important to develop new, environmentally safe plant protection methods. In this study, we have tested an essential oil (EO) obtained from Foeniculum vulgare for the mortality of Myzus persicae, an important polyphagous pest, its natural predator Harmonia axyridis, and Eisenia fetida as a representative of soil organisms. The EO, with its major compounds trans-anethole (67.9%) and fenchone (25.5%), was found to provide excellent efficacy against M. persicae (LC50 = 0.6 and LC90 = 2.4 mL L−1) while not causing any significant mortality of the tested non-target organisms. On the contrary, application of an insecticide based on the active substance alpha-cypermethrin not only caused mortality in the aphids, but also had a fatal negative effect on both the non-target organisms we tested, resulting in their high mortality. Our results indicate very high prospects for using the essential oil from F. vulgare in the development of environmentally safe botanical insecticides designed for plant protection against aphids.

Benelli G., Pavela R., Giordani C., Casettari L., Curzi G., Cappellacci L., Petrelli R., Maggi F.

The massive use of synthetic insecticides led to negative effects on the environment and human health. Therefore, researchers looked at natural products as effective alternatives to conventional pesticides. Here, commercially valuable essential oils (EOs) were selected from mint (Mentha x piperita, Mentha spicata), basil (Ocimum basilicum), helichrysum (Helichrysum italicum), yarrow (Achillea ligustica), geranium (Pelargonium odoratissimum), cinnamon (Cinnamomum verum) and ginger grass (Lippia alba). The chemical composition of these EOs assayed was analyzed by GC–MS. Then, we investigated their insecticidal potential in acute and sub-lethal toxicity assays against mosquito vectors of filariasis (Culex quinquefasciatus) and house flies (Musca domestica). Against C. quinquefasciatus 4th instar larvae, the most toxic EO was C. verum (LC50 = 40.7 μl L−1), followed by L. alba (LC50 = 59.6 μl L−1), while against M. domestica adults, the most toxic EOs were C. verum and H. italicum (LD50 = 42 μg adult−1). The exposure of mosquito larvae to a sub-lethal concentration (LC30 = 25 mg L−1) led to a reduction of adult emergence and fertility. Besides, adult flies that survived after exposure to a sub-lethal dose of C. verum EO (LD20 = 10 μg adult−1) showed a marked decrease in male and female longevity, as well as to a reduction in fecundity, fertility, and natality. Overall, C. verum and H. italicum EOs showed a highly promising insecticidal potential on two key insect vectors and pests. The relatively low prices of the selected EOs, their availability on the market and the noteworthy global production of the bulky materials, make them as ideal candidate ingredients to be used in insecticidal formulations.

Calzolari D., Magagnini G., Lucini L., Grassi G., Appendino G.B., Amaducci S.

Industrial hemp cultivation in Europe is dual-purpose, with stalks providing fibers and hurds, and seeds being used for food, feed and pharmaceutical applications. Economic sustainability of hemp cultivation should encompass the possibility of recovering non-narcotic secondary metabolites from hemp by-products (leaves, leaflets and bracts) originating from seed harvest and seed cleaning procedures. Surprisingly, no information is currently available on the contents of high added value bioactive compounds (CBD, CBG, cannflavin A, Δ9-THC) in industrial hemp inflorescence and threshing residues. This observation provided a rationale for investigating the issue on three monoecious varieties grown in Northern Italy. The concentration of target compounds was monitored from full-flowering until plant senescence by LC–MS/MS analysis of methanolic extracts of the plant biomass. The anti-inflammatory prenylated flavonoid cannflavin A was present in all varieties at levels mainly affected by genotype and air temperature. Conversely, the concentration of CBD, currently the clinically most promising non-narcotic cannabinoid, correlated to the overall extent and distribution of precipitation during growing cycle. Our findings suggest that postponing harvest after seed maturity increases the CBD contents and increase the CBD/Δ9-THC ratio in harvest threshing.

Stevenson P.C., Isman M.B., Belmain S.R.

Botanical insecticides provide a multitude of chemistries for the development of new pest management products. Despite relatively low rates of expansion of botanically based pesticides, regulatory changes in many parts of the world are driving a renaissance for the development of new natural pest control products that are safer for human health and the environment. Africa is arguably the continent with the most to gain from developing natural plant-based pesticides. Hundreds of indigenous and exotic species with pesticidal properties have been reported from Africa through various farmer surveys and subsequent research, many of which have been confirmed to be active against a range of arthropod pests. On-farm use of pesticidal plants, particularly among resource-poor small-holder farmers, is widespread and familiar to many African farmers. Until recently, the pyrethrum industry was dominated by East African production through small holder farmers, showing that non-food cash crop production of pesticidal plants is a realistic prospect in Africa when appropriate entrepreneurial investment and regulatory frameworks are established. This paper reviews the current status of research and commercialisation of pesticidal plant materials or botanically active substances that are used to control pests in Africa and establishes where major gaps lie and formulates a strategy for taking research forward.

Sut S., Pavela R., Kolarčik V., Lupidi G., Maggi F., Dall’Acqua S., Benelli G.

In the present work, we evaluated the toxicity and growth inhibitory effects on Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) of the root hexane extract from Onosma visianii (Boraginaceae). Furthermore, two naphtooquinone derivatives, namely isobutyrylshikonin and isovalerylshikonin, which were isolated from the extract by column chromatography and identified by Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS) techniques, were also assayed for the same target. The O. visianii extract, at 30.0 μg/cm 2 , led to 100% mortality at day 7, with LD 50 of 6.8 μg/cm 2 for the same day. On the other hand, isovalerylshikonin was significantly more effective (LD 50  = 0.8 μg/cm 2 ) than isobutyrylshikonin (LD 50  = 7.3 μg/cm 2 ). The two tested naphtoquinones inhibited the growth of S. littoralis larvae with ED 50 of 0.4 and 0.3 μg/cm 2 , respectively. Furthermore, isovalerylshikonin provide a stronger inhibition of acetylcholinesterase (AChE) enzyme (IC 50  = 51.4 μg/mL), than isobutyrylshikonin (IC 50  = 162.0 μg/mL). These findings provided new insights into the potential of shikonin derivatives as new valuable botanical insecticides to be used in crop protection.

Pavela R., Maggi F., Lupidi G., Cianfaglione K., Dauvergne X., Bruno M., Benelli G.

The effective management of insect pests and vectors still represents a major challenge in current entomology. Culex quinquefasciatus Say is a key vector of lymphatic filariasis, Rift Valley fever, West Nile, St. Louis encephalitis and Western equine encephalitis virus. Recently, the importance of the eco-friendly control of C. quinquefasciatus larval population using plant-borne biopesticides, including essential oils (EOs), has been stressed. Spodoptera littoralis (Boisd.) also known as tobacco cutworm, is one of the most destructive moth agricultural pests in tropic and sub-tropic regions. Despite the fact that sea fennel ( Crithmum maritimum L., Apiaceae) is considered as a promising biosaline crop, its potential for commercial cultivation has not yet been exploited. Notably, it has been reported that in coastal marine environments insect pests stay away from sea fennel plants. This aromatic plant is endowed with secretory structures as ducts and vittae storing volatile compounds. In the present study, the chemical composition of sea fennel essential oils from three different EO accessions, namely France (Brittany), Central and South Italy (Marche and Sicily regions) have been analysed by gas chromatography-mass spectrometry (GC–MS), and their toxicity against larvae of Cx. quinquefasciatus and S. littoralis was evaluated. Selected pure compounds from the essential oils mentioned above were also tested. The essential oils showed notable variability in chemical composition, being dominated by dillapiole and γ-terpinene (French EO), limonene and γ-terpinene (central Italy EO) and thymol methyl ether and γ-terpinene (Sicilian EO). As found out, the significantly most efficient essential oils were obtained from the seeds and aerial parts of plants of the French region. For these EOs, LD 50 values were estimated as 62.3 and 71.7 μg/larva for S. littoralis , respectively, and LC 50 as 13.7 and 15.6 μl/L for C. quinquefasciatus larvae, respectively. γ-Terpinene and myristicin were the most effective on C. quinquefasciatus larvae showing LC 50 values C. maritimum EO against mosquitoes and agricultural pests, allowing to identify the most effective chemotype, and to stimulate cultivation of this species as a source of botanical insecticides.

Benelli G., Pavela R., Lupidi G., Nabissi M., Petrelli R., Ngahang Kamte S.L., Cappellacci L., Fiorini D., Sut S., Dall’Acqua S., Maggi F.

In the attempt to exploit the potential of the monoecious fiber hemp cv. Futura 75 in new fields besides textile, cosmetics and food industry, its crop-residue given by leaves and inflorescences was subjected to hydrodistillation to obtain the essential oils. These are niche products representing an ideal candidate for the development of natural insecticides for the control and management of mosquito vectors, houseflies and moth pests. After GC-MS analysis highlighting a safe and legal chemical profile (THC in the range 0.004–0.012% dw), the leaf and inflorescence essential oils were investigated for the insecticidal potential against three insect targets: the larvae of Culex quinquefasciatus and Spodoptera littoralis and the adults of Musca domestica. The essential oil from inflorescences, showing (E)-caryophyllene (21.4%), myrcene (11.3%), cannabidiol (CBD, 11.1%), α-pinene (7.8%), terpinolene (7.6%), and α-humulene (7.1%) as the main components, was more effective than leaf oil against these insects, with LD50 values of 65.8 μg/larva on S. littoralis, 122.1 μg/adult on M. domestica, and LC50 of 124.5 μl/l on C. quinquefasciatus larvae. The hemp essential oil moderately inhibited the acetylcholinesterase (AChE), which is a target enzyme in pesticide science. Overall, these results shed light on the future application of fiber hemp crop-residue for the development of effective, eco-friendly and sustainable insecticides.

Benelli G., Romano D.

Benelli G., Beier J.C.

The effective and eco-friendly control of Anopheles vectors plays a key role in any malaria management program. Integrated Vector Management (IVM) suggests making use of the full range of vector control tools available. The strategies for IVM require novel technologies to control outdoor transmission of malaria. Despite the wide number of promising control tools tested against mosquitoes, current strategies for malaria vector control used in most African countries are not sufficient to achieve successful malaria control. The majority of National Malaria Control Programs in Africa still rely on indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs). These methods reduce malaria incidence but generally have little impact on malaria prevalence. In addition to outdoor transmission, growing levels of insecticide resistance in targeted vectors threaten the efficacy of LLINs and IRS. Larvicidal treatments can be useful, but are not recommended for rural areas. The research needed to improve the quality and delivery of mosquito vector control should focus on (i) optimization of processes and methods for vector control delivery; (ii) monitoring of vector populations and biting activity with reliable techniques; (iii) the development of effective and eco-friendly tools to reduce the burden or locally eliminate malaria and other mosquito-borne diseases; (iv) the careful evaluation of field suitability and efficacy of new mosquito control tools to prove their epidemiological impact; (v) the continuous monitoring of environmental changes which potentially affect malaria vector populations; (vi) the cooperation among different disciplines, with main emphasis on parasitology, tropical medicine, ecology, entomology, and ecotoxicology. A better understanding of behavioral ecology of malaria vectors is required. Key ecological obstacles that limit the effectiveness of vector control include the variation in mosquito behavior, development of insecticide resistance, presence of behavioral avoidance, high vector biodiversity, competitive and food web interactions, lack of insights on mosquito dispersal and mating behavior, and the impact of environmental changes on mosquito ecological traits. Overall, the trans-disciplinary cooperation among parasitologists and entomologists is crucial to ensure proper evaluation of the epidemiological impact triggered by novel mosquito vector control strategies.

Pavela R., Maggi F., Lupidi G., Mbuntcha H., Woguem V., Womeni H.M., Barboni L., Tapondjou L.A., Benelli G.

Dysphania ambrosioides (L.) Mosyakin & Clemants (Amaranthaceae) and Clausena anisata (Willd.) Hook. f. ex Benth. (Rutaceae) are two aromatic species traditionally used in Cameroon to repel and kill insects. The present work was carried out to substantiate this traditional use and to evaluate the possible incorporation in commercial botanical insecticides of their essential oils (EOs). The EOs were distilled from leaves of C. anisata and aerial parts of D. ambrosioides and analyzed by gas chromatography-mass spectrometry (GC-MS). The insecticidal activity of both EOs was investigated against the filariasis vector, Culex quinquefasciatus, and the housefly, Musca domestica. As possible mode of action, the inhibition of acetylcholinesterase (AChE) by the two EOs was investigated as well. The D. ambrosioides EO was characterized by the monoterpene peroxide ascaridole (61.4%) and the aromatic p-cymene (29.0%), whereas the C. anisata EO was dominated by the phenylpropanoids (E)-anethole (64.6%) and (E)-methyl isoeugenol (16.1%). The C. anisata EO proved to be very toxic to third instar larvae of C. quinquefasciatus showing LC50 of 29.3 μl/l, whereas D. ambrosioides EO was more toxic to adults of M. domestica showing a LD50 of 51.7 μg/adult. The mixture of both EOs showed a significant synergistic effect against mosquito larvae with LC50 estimated as 19.3 μl/l, whereas this phenomenon was not observed upon application to M. domestica adults (LD50 = 75.9 μg/adult). Of the two EOs, the D. ambrosioides one provided a good inhibition of AChE (IC50 = 77 μg/ml), whereas C. anisata oil was not effective. These findings provide new evidences supporting the ethno-botanical use of these two Cameroonian plants, and their possible application even in synergistic binary blends, to develop new eco-friendly, safe and effective herbal insecticides.

Vasantha-Srinivasan P., Senthil-Nathan S., Ponsankar A., Thanigaivel A., Chellappandian M., Edwin E., Selin-Rani S., Kalaivani K., Hunter W.B., Duraipandiyan V., Al-Dhabi N.A.

Comparative toxicity of two chemical pesticides (temephos and monocrotophos) versus a plant-derived betel leaf oil Piper betle (L.) to earthworm Eudrilus eugeniae (Kinberg) and redworm Eisenia fetida Savigny, historically: Eisenia foetida (Savigny 1826), was evaluated. Mortality rate was more prominent in temephos at 100 μg concentration to both the earthworms in filter paper test (FPT) as well as 10 mg concentration in artificial soil test (AST). In contrast, P. betle does not display much mortality rate to both the earthworms even at 1000 mg of treatment concentrations. The lethal concentration (LC50) value was observed at 3.89 and 5.26 mg/kg for temephos and monocrotophos against E. eugeniae and 3.81 and 5.25 mg/kg to E. fetida, respectively. Whereas, LC50 value of betel leaf oil was only observed at 3149 and 4081 mg/kg to E. eugeniae and E. fetida, respectively. Correspondingly, the avoidance or attraction assay also displayed that earthworms were more sensitive to the soil containing chemical pesticides. Whereas, the avoidance percentage was decreased in the P. betle oil. Similarly, sublethal concentration of chemical pesticides (5 and 6.5 mg) significantly reduced the earthworm weight and growth rate. However, P. betle oil did not change the developmental rate in the duration of the assay (2, 7 and 14 days) even at 4000 mg treatment concentration. The enzyme ratio of CAT and SOD was also affected significantly after exposure to the chemical pesticides (6.5 mg/kg). Hence, our study implied the risk assessment associated with the chemical pesticides and also recommends plant-derived harmless P. betle oil against beneficial species as an alternative pest control agent.

Vadivalagan C., Karthika P., Murugan K., Panneerselvam C., Del Serrone P., Benelli G.

Culex quinquefasciatus (Diptera: Culicidae) is a vector of many pathogens and parasites of humans, as well as domestic and wild animals. In urban and semi-urban Asian countries, Cx. quinquefasciatus is a main vector of nematodes causing lymphatic filariasis. In the African region, it vectors the Rift Valley fever virus, while in the USA it transmits West Nile, St. Louis encephalitis and Western equine encephalitis virus. In this study, DNA barcoding was used to explore the genetic variation of Cx. quinquefasciatus populations from 88 geographical regions. We presented a comprehensive approach analyzing the effectiveness of two gene markers, i.e. CO1 and 16S rRNA. The high threshold genetic divergence of CO1 (0.47%) gene was reported as an ideal marker for molecular identification of this mosquito vector. Furthermore, null substitutions were lower in CO1 if compared to 16S rRNA, which influenced its differentiating potential among Indian haplotypes. NJ tree was well supported with high branch values for CO1 gene than 16S rRNA, indicating ideal genetic differentiation among haplotypes. TCS haplotype network revealed 14 distinct clusters. The intra- and inter-population polymorphism were calculated among the global and Indian Cx. quinquefasciatus lineages. The genetic diversity index Tajima' D showed negative values for all the 4 intra-population clusters (G2-4, G10). Fu's FS showed negative value for G10 cluster, which was significant and indicated recent population expansion. However, the G2-G4 (i.e. Indian lineages) had positive values, suggesting a bottleneck effect. Overall, our research firstly shed light on the genetic differences among the haplotypes of Cx. quinquefasciatus species complex, adding basic knowledge to the molecular ecology of this important mosquito vector.

Benelli G., Pavela R., Canale A., Cianfaglione K., Ciaschetti G., Conti F., Nicoletti M., Senthil-Nathan S., Mehlhorn H., Maggi F.

Mosquito vector control is facing a number of important and timely challenges, mainly due to the rapid development of pesticide resistance and environmental concerns. In this scenario, screening of botanical resources for their mosquitocidal activity may offer effective and eco-friendly tools against Culicidae vectors. Culex quinquefasciatus Say (Diptera: Culicidae) is a vector of lymphatic filariasis and of dangerous arboviral diseases, such as West Nile and St. Louis encephalitis. In this study, the chemical composition of five essential oils obtained from different plants, namely Pinus nigra J.F. Arnold var. italica (Pinaceae), Hyssopus officinalis L. subsp. aristatus (Lamiaceae), Satureja montana L. subsp. montana (Lamiaceae), Aloysia citriodora Palau (Verbenaceae) and Pelargonium graveolens L'Hér (Geraniaceae), was investigated by GC-MS analysis. Furthermore, it was evaluated their acute toxicity on larvae of C. quinquefasciatus. Then, the most effective oils were selected, in order to focus on the potential synergistic and antagonistic effects, testing them in binary mixtures on C. quinquefasciatus larvae. Results showed that the higher effectiveness was obtained by S. montana subsp. montana essential oil (LC50=25.6μL·L-1), followed by P. nigra var. italica (LC50=49.8μL·L-1) and A. citriodora (LC50=65.6μL·L-1), while the other essential oils showed LC50 values higher than 90μL·L-1. The larvicidal effectiveness can be enhanced by preparing simple binary mixtures of essential oils, such as S. montana+A. citriodora (ratio 1:1), which showed higher larvicidal toxicity (LC50=18.3μL·L-1). On the other hand, testing S. montana+P. nigra (1:1) an antagonistic effect was detected, leading to a LC50 (72.5μL·L-1) higher than the LC50 values calculated for the two oils tested separately. Overall, our results add useful knowledge to allow the employ of synergistic essential oil blends as effective, cheap and eco-friendly mosquito larvicides.

Joy N., Jackson D., Coolong T.

ABSTRACTIntroductionTerpenes, which are found in high concentrations in the essential oil fraction of the Cannabis sativa flower, have demonstrated potential in many therapeutic and industrial applications.ObjectivesThis work reports on a method developed for quantifying 18 terpenes in C. sativa essential oil obtained through hydrodistillation. The following method has been evaluated for specificity, selectivity, accuracy, linearity, precision, stability, limit of detection, and limit of quantification.Materials and MethodsSamples were prepared by separating the essential oil fraction through hydrodistillation and then diluting with ethyl acetate containing a 100 μg/mL solution of n‐tridecane and octadecane as internal standards. Analysis was performed on a gas chromatograph mass spectrometer (GCMS) using selected ion monitoring (SIM).ResultsThe developed method enabled quantification of isomers of nerolidol and ocimene and several coeluting compounds, with recoveries of 87.35%–116.61%. Two cultivars of C. sativa flower were evaluated, and the dominant terpene compounds in both cultivars were β‐myrcene (5.85–8.62 mg/g dried plant) and β‐caryophyllene (3.89–4.69 mg/g), followed by α‐humulene (1.35–1.99 mg/g), limonene (0.91–1.33 mg/g), and α‐bisabolol (0.66–0.68 mg/g).ConclusionThis method provides an accurate and reliable procedure for separating and quantifying the major terpene compounds in C. sativa flower using hydrodistillation and GCMS with SIM. The simplicity and solvent‐free nature of the hydrodistillation extraction, combined with the specificity and accuracy of using SIM and external standards, enables the determination of total and individual terpenes concentrations within plant material and supports numerous industrial and therapeutic applications.

Pieracci Y., Pistelli L., D’Ambrosio B., Paris R., Flamini G., Bassolino L.

Industrial hemp (Cannabis sativa L.) is a versatile and sustainable multipurpose plant for agroecology services and a zero-waste circular economy. While the focus has traditionally been on primary products like fiber and seeds, nowadays there is an increasing awareness of the potential value of the by-products generated during hemp cultivation and processing. This article explores various methods of valorizing industrial hemp wastes, focusing on their mineral and biochemical composition, highlighting the benefits of utilizing what was once considered a mere by-product. The apical and the basal leaves of 12 industrial hemp varieties, six monoecious, and six dioecious, representing the main by-product of fiber supply chain, were assessed for their mineral (N, K, Na, Ca; Mg, Cu, Mn, Fe, and Zn), chlorophyll, carotenoids, and total soluble phenols contents, as well as for their antioxidant activity. The same parameters were also evaluated in the inflorescences; the main waste was derived from both hemp fiber and seed harvesting, which were collected at three stages of flower development for four selected genotypes, together with the yield and chemical composition of their essential oils. Differences in the evaluated parameters among genotypes and tissues were highlighted, showing the potential for diversifying the utilization of industrial hemp wastes. The possible uses of these residual biomasses are discussed based on their composition.

Ghosh D., Kundu A., Chaudhary N., Gupta D., Dwivedi M., Verma R.S., Kumar B., Shanker K., Kumar N.

ABSTRACTCannabis sativa L. is an important medicinal plant with high commercial value. In recent years, the research interest in cannabidiol (CBD) and terpene‐rich cannabis has been rapidly expanding due to their high therapeutic potential. The present study aims to explore the phytocannabinoids and terpenes diversity in C. sativa collected from different parts of northern India. Our findings revealed that the cannabinoids and terpenes synthesize together in capitate stalked and capitate sessile glandular trichomes, whereas bulbous glands synthesize only terpenes. The North Indian C. sativa is mainly dominated by tetrahydrocannabinol. The CBD‐rich plant diversity is nominal (1.11%) in studied north Indian C. sativa. The essential oil profiling reveals (E)‐caryophyllene (10.30%–36.80%) as the major constituent, followed by α‐humulene (0.50%–15.29%) and α‐bisabolol (0.00%–16.40%) in the North Indian population. The cannabinoids and terpenes content showed significant diversity among and within the five studied populations. The correlation analysis between cannabinoids and terpenes indicates that α‐pinene, β‐pinene and limonene positively correlated with CBD content. Similarly, α‐ and β‐selinene correlate positively with tetrahydrocannabinolic acid content. This study could help to identify the key cultivars from India and establish a consistent chemotype for future breeding programs.

Karthik Raja R., Prabu Kumar S., Balasubramani G., Sankaranarayanan C., Liu B., Hazir S., Narayanan M.

Excessive chemical pesticide use has had harmful implications for the environment, animals and humans. Insect resistance has substantially resulted in reduced pesticide efficiency. Global experts are striving to diminish the use of harmful pesticides for pest and pathogen control by adopting eco-friendly methods. Nanotechnology, a recent breakthrough, holds significant promise in addressing these challenges and providing safer environmental alternatives. Nanotechnology applications in sustainable agriculture have tremendous potential in insect pest management with controlled and targeted release mechanisms as smaller sizes of the nanoparticles ensure the proper spread on the pest surface, which results in better action. Biological synthesis of these nanoparticles from plant parts and microorganisms is a valuable alternative to chemical approaches. Nanotechnology is used in formulating nano-based pesticides such as nanosuspensions, nanocapsules and nanoclays. In addition, some nanoparticles are used as pesticides alone. This review covers the significance of bio-nano-insecticides, their synthesis, and formulations as modern pesticides. Additionally, it highlights the previously less-explored impact of nanoparticles on mosquito larvae. The study also encompasses nanopesticide formulation, delivery, mode of action, and effects on non-target species. Furthermore, difficulties and limitations must be resolved and investigated in order to evaluate the laboratory results of nanoparticle application for commercialization. This review also discusses the challenges and limitations hindering the commercialization of nanoparticle applications in insect control. Addressing these challenges is essential to ensure the successful translation of laboratory results into practical and effective pest management solutions.

Rezghiyan A., Esmaeili H., Farzaneh M.

Various practical strategies have been employed to mitigate the detrimental effects of water deficit stress on plants such as application of nano-stimulants. Nanosilicon plays a crucial role in alleviating the deleterious impacts of both abiotic and biotic stresses in plants by modulating various phyto-morphological and physiological processes. This study aimed to examine the combined effects of drought stress and nanosilicon application on the morphological traits and essential oil content and compositions of hemp (Cannabis sativa L.), in which four-week-old seedlings were subjected to irrigation treatments at four levels, including 100% (control), 80% (mild stress), 60% (moderate stress) and 40% (severe stress) field capacity and nanosilicon at three concentrations (0, 0.5 and 1.5 mM) in a completely randomized factorial design experiment with three replications for 40 days. The results showed that the maximum plant height (109.07 cm), number of nodes (33.3), and number of flowering branches (29.4) were recorded under the treatment of 1.5 mM nanosilicon and 100% FC. The lowest fresh and dry weights of aerial parts were associated to the severe drought stress (40% FC) without nanosilicon application. The mild water stress (80% FC) combined with foliar application of 1.5 mM nanosilicon led to highest EO content (0.17%) compared with the other treatments. However, the highest content of cannabidiol in the essential oil was achieved in the severe water stress (40% FC) and treatment of 0.5 mM nanosilicon. The results showed that the application of nanosilicon improved the morphological characteristics and also changed the content and compositions of the hemp plants under drought stress conditions.

Dogbe W., Revoredo-Giha C., Russell W.

Abstract Background The growing demand for eco-friendly food and industrial products have renewed interest in industrial hemp which is a low-cost, biodegradable, sustainable, and multi-purpose plant. Many countries in Europe and Asia have changed their laws to take advantage of the tremendous benefits that industrial hemp present. However, the development of the sector in Scotland is very slow due to stringent laws. The goal of the present study is to present policymakers with economic data on the current and potential market opportunities for industrial hemp, trends in new product development, and the state of the hemp supply chain. This study entails desk-based research primary and secondary data analysis. Primary data were collected from farmers in Aberdeenshire and Scottish borders, and secondary data were collected from the FAOSTATS Office of National Statistics and the Global New Product Database. Results The results of this study show that the opportunities from hemp seed and fibre are vast: hemp can sequester more carbon dioxide than traditional crops can, improve soil biodiversity, extract toxins from soil through phytoremediation, be used as an eco-friendly insecticide and pesticide, and provide an excellent source of protein, fibre and micronutrient vitamins and minerals, as well as a range of bioactive phytochemicals. The GNPD reveals that over 4000 hemp-based products have been launched worldwide. However, the supply chain for Scottish-grown hemp faces significant bottlenecks. The sector lacks a well-established market route, faces a high licensing costs, lacks hemp seed-pressing centres, etc. Conclusion This study is relevant because it is the first study to provide a comprehensive analysis of the industrial hemp sector in Scotland. This study makes time-bound recommendations to grow the hemp sector in Scotland, which include regular extension services, easy access to licences for production, the establishment of a hempseed and fibre processing plants, and seed production centre.

Leede A.E., Davis J.A.

Abstract Industrial hemp, Cannabis sativa L., is an herbaceous annual plant that has recently re-entered crop production both in the field and in greenhouses within the United States. Like many agronomic crops, hemp production faces several insect pest challenges. Aphids pose a unique threat to hemp, being found in both indoor and outdoor production. Aphids affect hemp by reducing plant growth, bud production, concentrations of cannabinoids, and removing photosynthate. Additionally, aphids are vectors of plant viruses, and several species are known to transmit viruses to hemp. Limited research exists regarding the host suitability of hemp for common aphid pests in Louisiana. Thus, experiments were conducted to determine the life table statistics and feeding behaviors of Myzus persicae, Aphis gossypii, and Phorodon cannabis to determine the potential pest population dynamics of these pests on hemp. Hemp cv. Maverick was not a good host for either A. gossypii or M. persicae, resulting in negative intrinsic rates of increase and no sustained colonization. Although individuals of M. persicae and P. cannabis initiated probes at comparable rates, M. persicae probe durations were significantly shorter and probes were more frequent, indicating an absence of positive responses to probing hemp. A significant difference was observed in the percentage of individuals of A. gossypii initiating probes, and probe duration was significantly shorter than P. cannabis and significantly longer than M. persicae. Both A. gossypii and M. persicae spent significantly less time probing in phloem when compared with P. cannabis. These electrical penetration graph results indicate that A. gossypii and M. persicae do not find C. sativa cv. Maverick a suitable host; however, both species of aphids may still pose a threat to C. sativa production as virus vectors.

Williams A.M., Sbrizzi S., Campbell L.G., Koprivnikar J.

Given the rise in cannabis ( Cannabis sativa L .) cultivation, and the absence of disposal guidelines in Canada and other countries, the toxicological impacts of its secondary metabolites on non-target organisms via ingestion are important to understand. Due to the unique chemicals found in C. sativa, sublethal effects, such as those on behaviours and growth, must also be considered. We fed a generalist detritivore, the red wiggler earthworm ( Eisenia fetida (Savigny, 1826)), diets composed of hemp or two other crop plants (lettuce or basil), or combinations thereof, over 28 days to measure effects on earthworm survival, growth, and behavioural responses to stressful stimuli (high heat and light). Earthworms fed only hemp gained weight, albeit less than those on other diets, with no effects on their survival or response to light. However, hemp consumption led to slower escape times and speeds from a heat stimulus, indicating potential sublethal effects. By using hemp genotypes with low cannabinoid concentrations, our results offer a conservative estimate of the potential impact of hemp cultivation or disposal of C. sativa on invertebrates such as earthworms. This research underscores the importance of developing accurate risk models for exposure to crop phytochemicals in non-target species.

Gao S., Guo M., Yu W., Miao W., Ya H., Liu D., Li R., Zhang K.

AbstractThe red flour beetle, Tribolium castaneum, is an agricultural and storage pest with a global distribution. Studies have shown that eucalyptol has strong contact toxicity against larvae of this beetle, whereas odorant binding proteins (OBPs) are known to contribute to larval defenses against this phytochemical toxin. However, the mechanisms underlying the protective effect of insect OBPs against eucalyptol remain unclear. Here, TcOBPC02 from T. castaneum was cloned and characterized. Gene expression profile analysis showed that TcOBPC02 is highly expressed at early larval and early pupal stages. Additionally, tissue expression profiling revealed that, in the adult, TcOBPC02 was most highly expressed in the head, followed by the epidermis, whereas in larvae, TcOBPC02 was mainly expressed in hemolymph and the epidermis. These developmental stages and tissues that exhibit high TcOBPC02 expression are closely related to the detoxification of heterologous substances. Furthermore, the mRNA level of TcOBPC02 was significantly increased after exposure to eucalyptol, whereas TcOBPC02‐targeted RNA interference increased the susceptibility of T. castaneum to eucalyptol, indicating that TcOBPC02 participates in the tolerance of this beetle to eucalyptol. Additionally, recombinant TcOBPC02 was expressed in Escherichia coli and isolated, enabling a straightforward fluorescence competition binding assay. In combination, these results have demonstrated that TcOBPC02 is required for defenses against phytochemicals in T. castaneum. This study provides a theoretical basis for understanding the mechanisms underlying the degradation of exogenous toxicants in insects and adds to the repertoire of potential target genes for pest control.

Hagerty C.H., Shrestha G., Wen N., Kroese D.R., Namdar G.F., Paulitz T., Wysocki D.J.

The predominant cropping scheme for dryland wheat production in the Pacific Northwest (PNW) region of the United States includes winter wheat–summer fallow. Lack of crop diversification can deplete the soil organic matter and nutrients, while favoring the build-up of soilborne diseases. Cover crops are becoming more common within a standard rotation, primarily to provide protection against soil erosion, incorporate nutrients, and break soilborne diseases’ cycles. In this study, we investigated the potential of using hemp as a cover crop in a dryland wheat rotation to reduce soilborne diseases, and thus increase farmers’ profitability. While the benefits of barley and yellow mustard cover crops are well understood, the benefits of a hemp cover crop have not been examined in the PNW. We observed Fusarium spp. disease suppression on winter wheat following a hemp cover crop in the greenhouse studies. However, under field conditions, we did not observe a difference in pathogen abundance on winter wheat following hemp cover crop and hemp amendments in the field. Any potential to limit soilborne disease is a profitability opportunity for farmers. Our findings indicate that incorporating a hemp rotation into the PNW dryland wheat production system holds promise as a strategy to reduce soilborne diseases and improve soil health, though further research is necessary to confirm its effectiveness and underlying mechanism.

Ayllón-Gutiérrez R., Díaz-Rubio L., Montaño-Soto M., Haro-Vázquez M.D., Córdova-Guerrero I.

Essential oils (EOs) are volatile products derived from the secondary metabolism of plants with antioxidant, antimicrobial, and pesticidal properties. They have traditionally been used in medicine, cosmetics, and food additives. In agriculture, EOs stand out as natural alternatives for pest control, as they show biocidal, repellent, and antifeedant effects. However, they are highly volatile compounds and susceptible to oxidation, which has limited their use as pesticides. This has led to exploring micro- and nano-scale encapsulation to protect these compounds, improving their stability and allowing for a controlled release. Various encapsulation techniques exist, such as emulsification, ionic gelation, and complex coacervation. Nanoemulsions are useful in the food industry, while ionic gelation and complex coacervation offer high encapsulation efficiency. Materials such as chitosan, gelatin-gum-Arabic, and cyclodextrins are promising for agricultural applications, providing stability and the controlled release of EOs. Encapsulation technology is still under development but offers sustainable alternatives to conventional agrochemicals. This article reviews the potential of EOs in pest management and encapsulation techniques that enhance their efficacy.

Falcon-Brindis A., Villanueva R.T.

Pest management on hemp is still in its infancy, and biological control options are limited. Helicoverpa zea (corn earworm) is one of the key pests of hemp cultivated outdoors, especially on cultivars grown for cannabinoids and grain. In a three-year study, we assessed the effect of diet on the performance of H. zea and its tachinid parasitoids. Parasitized (bearing fly eggs) and unparasitized (without eggs) H. zea larvae were fed on hemp flowers or an artificial diet. Five tachinid species parasitized H. zea larvae, but the most abundant species were Winthemia rufopicta (68.8%) and Lespesia aletiae (28.3%). Overall, 55.2% of H. zea larvae bearing tachinid eggs died, while the mortality of unparasitized larvae reached 24.7%. The success of tachinids increased by 2-fold when the host larvae were fed on an artificial diet. Our results demonstrated that high protein food (artificial diet), intensity of parasitism, and caterpillar size play a role in the fitness of both the herbivores (H. zea) and its tachinid parasitoids. These findings have important implications for understanding biological control mechanisms and open new insights into the impact of landscape variation on plant-herbivore-parasitoid interactions. This study contains supporting evidence that makes both Winthemia rufopicta and Lespesia aletiae excellent candidates for biological control programs against H. zea, a key pest of hemp in the United States.

Nwanade C.F., Wang M., Pei T., Meng J., Yu Z., Liu J.

Plant essential oils (EOs)-based acaricides have been recognized as environmentally-friendly alternatives to synthetic acaricides because of their low toxicity against non-target species. Despite this, there are knowledge gaps regarding the toxicity mechanisms of plant EOs against non-target species. Here, the toxicology and enzymatic mechanism of Citrus reticulata and Citrus lemon EOs were evaluated against the vector pest, Haemaphysalis longicornis, and non-target ladybird beetle, Harmonia axyridis. Both EOs were mainly composed of d-Limonene, followed by β-Myrcene and γ-Terpinene in C. reticulata, and (-)-β-Pinene and γ-Terpinene in C. lemon. Citrus reticulata and C. lemon EOs were toxic to Hae. longicornis, with 50 % lethal concentration (LC

Ahmadi F., Kallinger D., Starzinger A., Lackner M.

Hemp (Cannabis sativa L.), renowned for its applications in environmental, industrial, and medicinal fields, is critically evaluated in this comprehensive review focusing on the impacts of chemical and organic fertilizers on its cultivation. As hemp re-emerges as a crop of economic significance, the choice between chemical and organic fertilization methods plays a crucial role in determining not only yield but also the quality and sustainability of production. This article examines the botanical characteristics of hemp, optimal growth conditions, and the essential biochemical processes for its cultivation. A detailed comparative analysis is provided, revealing that chemical fertilizers, while increasing yield by up to 20% compared to organic options, may compromise the concentration of key phytochemicals such as cannabidiol by approximately 10%, highlighting a trade-off between yield and product quality. The review presents quantitative assessments of nitrogen (N), phosphorus (P), and potassium (K) from both fertilizer types, noting that K significantly influences the synthesis of terpenes and cannabinoids, making it the most impactful element in the context of medicinal and aromatic hemp varieties. Optimal rates and timing of application for these nutrients are discussed, with a focus on maximizing efficiency during the flowering stage, where nutrient uptake directly correlates with cannabinoid production. Furthermore, the challenges associated with the U.S. industrial hemp market are addressed, noting that reducing production costs and improving processing infrastructure is essential for sustaining industry growth, especially given the slow expansion in fiber and cannabidiol markets due to processing bottlenecks. The review concludes that while chemical fertilizers may offer immediate agronomic benefits, transitioning towards organic practices is essential for long-term environmental sustainability and market viability. The future of the hemp industry, while promising, will depend heavily on advancements in genetic engineering, crop management strategies, and regulatory frameworks that better support sustainable cultivation practices. This nuanced approach is vital for the industry to navigate the complex trade-offs between productivity, environmental health, and economic viability in the global market.

Vinciguerra V., Di Martile M., Mollica Graziano M., Del Bufalo D., Garzoli S.

Cannabis sativa L. is a plant that has been cultivated since ancient times thanks to its various uses. Even its extraction products, such as essential oil and hydrolate, having a varied chemical composition and rich in bioactive components, find wide use in different sectors, gathering ever-increasing interest over time. In this work, the essential oil of Cannabis sativa L. cv. Carmagnola was characterized by using Gas Chromatography/Mass Spectrometry (GC/MS) and, for the first time, the chemical profile of the hydrolate was also described through different analytical techniques such as Large-Volume Injection Gas Chromatography/Mass Spectrometry (LVI-GC/MS) and Direct Immersion-Solid Phase Microextraction-Gas Chromatography/Mass spectrometry (DI-SPME-GC/MS), in order to provide a more complete compositional profile. The results of the analyses conducted on the hydrolate highlighted a high content of α-terpineol; on the other side, in the essential oil, a prevalence of monoterpenes, with α-pinene and limonene as the characterizing components, was detected. Both matrices were also investigated to evaluate their cytotoxic activity by using a panel of cancer cell lines derived from different histotypes such as melanoma (A375, LOX IMVI), non-small cell lung cancer (H1299, A549), colon (HT29) and pancreatic (L3.6) cancer cell lines. The obtained data demonstrated that essential oil was more effective than hydrolate in terms of reduction in cell viability.