Aphicidal activity of farnesol against the green peach aphid – Myzus persicae

BACKGROUND: Myzus persicae (Hemiptera: Aphididae) is considered one of most important agricultural pests in the world. It is one of the main pests in protected pepper crops under glasshouse conditions in Southeastern Spain, but its control is limited as a consequence of the few available authorized insecticides and their incompatibility with the natural enemies. Some essential oils and pure compounds such as anise (Pimpinella anisum) or farnesol are repellent and/or toxic to aphids. Their use as a botanical insecticides can be an alternative for aphid control in pepper. RESULTS: The effect of farnesol was evaluated against M. persicae in a new bioassay developed to test the contact effect (aqueous formulation of the products) on aphids in laboratory conditions. Aniseed essential oil, geraniol and (Z)-jasmone at 0.6% causes an aphid mortality of >50%; and farnesol was the most effective (93.67% mortality). Farnesol nanoemulsions between 0.2% and 0.6% were formulated with an IKA-Labor Pilot dispersing machine (7940 rpm for 10 min) using Tween 80 as a surfactant. These formulations were tested on field experiments (glasshouse conditions) on pepper crops for 2 years. Foliar applications of farnesol at a concentration of 0.4% in field conditions causes a high reduction in aphid populations, with efficacies of ≈70–80% with respect to the control, similar to or even higher than the efficacy of the reference pyrethrin insecticide. CONCLUSION: Farnesol showed a great aphicidal effect against M. persicae. The use of this molecule in integrated pest management programs combined with natural enemies is a good option for future control of M. persicae

Aniseed essential oil botanical insecticides for the management of the currant-lettuce aphid

Nasonovia ribisnigri Mosley (Hemiptera: Aphididae) is the most damaging aphid species of lettuce grown in open fields. Populations of N. ribisnigri are developing resistance to insecticides, making their control difficult. Botanicals are an alternative for pest control. Aniseed (Pimpinella anisum L.) is a relevant crop in the production of essential oils. The effect of aqueous nano-formulations of this oil and its main compound (E)-anethole were tested against N. ribisnigri in a growth chamber, a greenhouse (in spring for two years, 2019 and 2020) and in the open field in a plot in the Southeast of Spain (Torrepacheco, Murcia) in May 2019. Aniseed essential oil nanoemulsions were prepared using a laboratory dispersing machine at a high-speed regime (10 min, 7940 revs/min, 15 ◦C) using Tween80 as a surfactant at a 1:2 ratio. Foliar applications of aniseed essential oil at concentrations of 0.2% and 0.4% (0.1 and 0.2 mL respectively) to lettuce plants infested with homogeneous populations of N. ribisnigri reduced the number of insects compared with the control in the laboratory (efficacies > 50%) and greenhouse (efficacies > 25%, 48 h after treatment) experiments. During the field trial, a reduction in the aphid populations was also produced after the application of the products, without any phytotoxic effects observed on the crop. Likewise, (E)-anethole gave similar results as aniseed essential oil (with efficiencies of up to 47% with respect to the control) without damaging the plant

Fumigant Toxicity in Myzus persicae Sulzer (Hemiptera: Aphididae): Controlled Release of (E)-anethole from Microspheres

(E)-anethole is a phenylpropanoid that is the main compound found in the essential oils (EOs) of anise and fennel seeds, and either fumigant or direct contact activity of this compound has been demonstrated against aphids and stored product pests. In this work, solid microspheres were prepared by three methods—oil emulsion entrapment, spray-drying, and complexed with β-cyclodextrin. Fumigation activity of each microsphere preparation was tested against the green peach aphid, Myzus persicae Sulzer (Hemiptera: Aphididae), on pepper leaves. The best insecticidal activity was with (E)-anethole encapsulated in oil emulsion beads and introduced to aphids as a vapour over 24 h, with an LC50 of 0.415 μL/L compared to 0.336 μL/L of vapors from free (E)-anethole. Scanning electron microscopy of the beads revealed a compact surface with low porosity that produced a controlled release of the bioactive for more than 21 d, whilst most of the volatile was evaporated within two days if applied unformulated. Spray drying gave spherical particles with the greatest encapsulated yield (73%) of 6.15 g of (E)-anethole incorporated per 100 g of powder. Further work will be done on improving the formulation methods and testing the solid microspheres in all aphid stages scaling up the experimental assay. It is foreseen that nanotechnology will play a role in future developments of low risk plant protection product

Plant bioactive volatile products and their efficiency in aphid control

The “farm-to-fork strategy” of the European Union aims to reduce dependency on pesticides and towards increased use of low-risk products, such as those based on botanical extracts. A product based on the mixture of the five natural compounds selected for their repellent or insecticidal properties, namely citral, (E)-anethole, farnesol, cis-jasmone and lemon essential oil, was evaluated against Myzus persicae Sulzer (Hemiptera: Aphididae). Three formulations were prepared using various surfactants at different ratios: the first one with Tween80, the second one with soy (Glycine max (l.) Merr.) lecithin and the third one with soy lecithin and sunflower oil (Helianthus annuus L.). The oil-in-water nanoemulsions at 1% were tested in a laboratory study with Petri dishes using a computer-controlled spraying apparatus (equivalent application of 200 l/ha). The mean efficacy was 45%, 71% and 63%, respectively, with a least statistically significant difference (LSD) at 5% comparing the first two formulations. A field experiment (in two pepper, Capsicum anuum L., greenhouses) at Torreblanca Exp. Stat. in Murcia (Spain) followed in April 2020 in which a reduction in aphid populations only occurred by spraying the product formulated with soy lecithin. Phytotoxicity was also observed but was lower in the formulation that contained sunflower oil. Nanoemulsions were characterised using a Zetasizer, and a polydispersion of 2–3 populations of particles, ranging from 15 to 341 nm in size, was found with the Tween80 formulation and bigger sizes (250–438 nm) with the soy lecithin and sunflower oil formulation, which were more stable (Z potential = −28.15 mV). The application of ultrasounds reduces the Z-average to 100 nm in the mixture product with stability for at least 14 days. Another field experiment was repeated in February and April 2021. The plants were sprayed sequentially with the following: a) mixture product at 0.5% formulated with soy lecithin and sunflower oil, b) 3% cottonseed (Gopsyppium hirsutum L.) oil in 3% soap water (Feb.) or 1.5% cottonseed oil in 1.5% soap water (Apr.) and c) cis-jasmone at 0.25% formulated with Tween80. The treatment with the mixture of bioactive volatiles (a) was not more effective than that of the fixed seed oil (b). In February, the instantaneous population growth rate (ri) of aphid populations showed a significant reduction when the plants were sprayed with cottonseed oil. Further research is recommended for the formulation and application methods of the products being develope

Use of nanoemulsions of plant essential oils as aphid repellents

It is believed that climate change will greatly impact the relative importance of pests. The bird cherry-oat aphid, Rhopalosiphum padi L. is probably the major pest of temperate cereal crops on a world scale, it attacks all the major cereals and pasture grasses. The organic sector is in need of alternative aphicides or products that can repel this pest. In spite of the properties of plant volatiles that allow them to act as insect repellents, there is a lack of such products on the market for the agricultural sector. In this work, we tested a group of essential oils and pure compounds in a laboratory choice bioassay with R. padi (20 replications per product) and the repellency index (R.I.) was computed after 24 h. At 0.15 μl/cm2, aniseed, peppermint and lemongrass essential oils were repellent for apterous females. trans-Anethole and caryophyllene exhibited volatile toxicity to the insects (LD50 =0.11 μl/cm2). R.I. values ranging from 68.8 to 100 were obtained using farnesol, geraniol, cisjasmone, citral, linalool, estragole, pulegone and caryophyllene. Water emulsions of the active products were obtained (nanoemulsions with oil droplets less than 100 nm via ultrasounds for 10 min) and applied at increasing volumes using a computer-controlled spraying apparatus for the bioassay, and a dose response was obtained. Some products were active: carvone increased mobility, whilst cis-jasmone repelled R. padi at a very low dose (0.02 μl/cm2 of the treated leaf). Zetasizer measurements indicated that the smaller the particle size within the nanoemulsion, the higher the activity. Using lecithin (1:2) or lecithin plus glycerol (1:2:1) in addition to a bioactive produced larger negative Z-potential values and therefore more stable formulations without any evident effect on activity

Yield of new hemp varieties for medical purposes under semi-arid Mediterranean environment conditions

Under the effects of climate change new drought tolerant crops are imperative to introduce in irrigated agricultural areas of Mediterranean countries. In this sense, hemp (Cannabis sativa L.) represents an alternative in many semi-arid agricultural areas of Mediterranean basin because of its low water requirements and cost effectiveness when it is developed under non controlled conditions. The aim of this work was to evaluate the potential yield of five new hemp varieties (Sara, Pilar, Aida, Theresa, and Juani) cultivated under high tunnel conditions in a semi-arid Mediterranean area, and also to study the effect of plant density on active biomass production and cannabinoids biosynthesis (cannabidiol, CBD and cannabigerol, CBG) at different plant positions. The trial was conducted under plastic macro-tunnels during two seasons (2014 and 2015), from May to October. The agronomic response and the chemical profiles of the studied varieties were evaluated at the end of each season. Moreover, it was monitored the differentiation in terms of active biomass production and cannabinoids biosynthesis in different plant organ positions (at upper, medium, and lower). Additionally, during the second season, three different plant densities (PD1, 9,777; PD2, 7,333; and PD3, 5,866 plants· ha-1) were tested in order to define the the best of them for maximizing CBD and CBG productions. The findings highlighted significant differences in yield between cultivars within the CBD and CBG. Moreover, plant density was a determinant factor related to active biomass production and cannabinoids contents, PD3 representing a suitable strategy to maximize the cannabinoids production minimizing the requirements of rooted apical cuttings. These results allowed concluding that these new hemp cultivars together with the adopted agronomic practices in this experience would be very appropriate for CBD and CBG productions, being determinant to consider the plant density and the cultivar for both studied chemotypes.Under the effects of climate change new drought tolerant crops are imperative to introduce in irrigated agricultural areas of Mediterranean countries. In this sense, hemp (Cannabis sativa L.) represents an alternative in many semi-arid agricultural areas of Mediterranean basin because of its low water requirements and cost effectiveness when it is developed under non controlled conditions. The aim of this work was to evaluate the potential yield of five new hemp varieties (Sara, Pilar, Aida, Theresa, and Juani) cultivated under high tunnel conditions in a semi-arid Mediterranean area, and also to study the effect of plant density on active biomass production and cannabinoids biosynthesis (cannabidiol, CBD and cannabigerol, CBG) at different plant positions. The trial was conducted under plastic macro-tunnels during two seasons (2014 and 2015), from May to October. The agronomic response and the chemical profiles of the studied varieties were evaluated at the end of each season. Moreover, it was monitored the differentiation in terms of active biomass production and cannabinoids biosynthesis in different plant organ positions (at upper, medium, and lower). Additionally, during the second season, three different plant densities (PD1, 9,777; PD2, 7,333; and PD3, 5,866 plants· ha-1) were tested in order to define the the best of them for maximizing CBD and CBG productions. The findings highlighted significant differences in yield between cultivars within the CBD and CBG. Moreover, plant density was a determinant factor related to active biomass production and cannabinoids contents, PD3 representing a suitable strategy to maximize the cannabinoids production minimizing the requirements of rooted apical cuttings. These results allowed concluding that these new hemp cultivars together with the adopted agronomic practices in this experience would be very appropriate for CBD and CBG productions, being determinant to consider the plant density and the cultivar for both studied chemotypes

Distinct conformational behaviors of four mammalian dual‐flavin reductases (cytochrome P450 reductase, methionine synthase reductase, neuronal nitric oxide synthase, endothelial nitric oxide synthase) determine their unique catalytic profiles

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109651/1/febs13073.pd

Distinct Conformational Behaviors of Four Mammalian Dual-Flavin Reductases (Cytochrome P450 Reductase, Methionine Synthase Reductase, Neuronal Nitric Oxide Synthase, Endothelial Nitric Oxide Synthase) Determine Their Unique Catalytic Profiles

Multidomain enzymes often rely on large conformational motions to function. However, the conformational setpoints, rates of domain motions and relationships between these parameters and catalytic activity are not well understood. To address this, we determined and compared the conformational setpoints and the rates of conformational switching between closed unreactive and open reactive states in four mammalian diflavin NADPH oxidoreductases that catalyze important biological electron transfer reactions: cytochrome P450 reductase, methionine synthase reductase and endothelial and neuronal nitric oxide synthase. We used stopped-flow spectroscopy, single turnover methods and a kinetic model that relates electron flux through each enzyme to its conformational setpoint and its rates of conformational switching. The results show that the four flavoproteins, when fully-reduced, have a broad range of conformational setpoints (from 12% to 72% open state) and also vary 100-fold with respect to their rates of conformational switching between unreactive closed and reactive open states (cytochrome P450 reductase \u3e neuronal nitric oxide synthase \u3e methionine synthase reductase \u3e endothelial nitric oxide synthase). Furthermore, simulations of the kinetic model could explain how each flavoprotein can support its given rate of electron flux (cytochrome c reductase activity) based on its unique conformational setpoint and switching rates. The present study is the first to quantify these conformational parameters among the diflavin enzymes and suggests how the parameters might be manipulated to speed or slow biological electron flux

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries