Conventional Pesticides Research Articles

New biologically active ionic liquids with benzethonium cation-efficient SAR inducers and antimicrobial agents.

An urgent need to find new methods for crop protection remains open due to the withdrawal from the market of the most toxic pesticides and increasing consumer awareness. One of the alternatives that can be used in modern agriculture is the use of bifunctional compounds whose actions towards plant protection are wider than those of conventional pesticides. In this study, we present the investigation of the biological efficacy of nine dual-functional salts containing a systemic acquired resistance (SAR)-inducing anion and the benzethonium cation. A significant result of the presented study is the discovery of the SAR induction activity of benzethonium chloride, which was previously reported only as an antimicrobial agent. Moreover, the concept of dual functionality was proven, as the application of presented compounds in a given concentrations resulted both in the control of human and plant bacteria species and induction of SAR. The strategy presented in this article shows the capabilities of derivatization of common biologically active compounds into their ionic derivatives to obtain bifunctional salts. This approach may be an example of the design of potential new compounds for modern agriculture. It provides plants with two complementary actions allowing to provide efficient protection to plants, if one mode of action is ineffective. © 2024 Society of Chemical Industry.

Transcriptomic and biochemical insights into fall armyworm (Spodoptera frugiperda) responses on silicon-treated maize.

The fall armyworm, Spodoptera frugiperda, is an agricultural pest of significant economic concern globally, known for its adaptability, pesticide resistance, and damage to key crops such as maize. Conventional chemical pesticides pose challenges, including the development of resistance and environmental pollution. The study aims to investigate an alternative solution: the application of soluble silicon (Si) sources to enhance plant resistance against the fall armyworm. Silicon dioxide (SiO2) and potassium silicate (K2SiO3) were applied to maize plants via foliar spray. Transcriptomic and biochemical analyses were performed to study the gene expression changes in the fall armyworm feeding on Si-treated maize. Results indicated a significant impact on gene expression, with a large number of differentially expressed genes (DEGs) identified in both SiO2 and K2SiO3 treatments. Furthermore, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis identified critical DEGs involved in specific pathways, including amino acid, carbohydrate, lipid, energy, xenobiotics metabolisms, signal transduction, and posttranslational modification, significantly altered at both Si sources. Biochemical analyses further revealed that Si treatments inhibited several enzyme activities (glutamate dehydrogenase, trehalase, glucose-6-phosphate dehydrogenase, chitinase, juvenile hormone esterase, and cyclooxygenase while simultaneously inducing others (total protein, lipopolysaccharide, fatty acid synthase, ATPase, and cytochrome P450), thus suggesting a toxic effect on the fall armyworm. In conclusion, Si applications on maize influence the gene expression and biochemical activities of the fall armyworm, potentially offering a sustainable pest management strategy.

Putative Role of Anti-microbial Peptide Recovered from Lactiplantibacillus spp. in Biocontrol Activity.

Antimicrobial peptides (AMPs) stand as a promising alternative to conventional pesticides, leveraging a multifaceted approach to combat plant pathogens. This study focuses on identifying and characterizing the AMP produced by Lactiplantibacillus argentoratensis strain IT, demonstrating potent antibacterial activity against various harmful microorganisms. Evaluation of AMPs' antibacterial activity was conducted through an agar well diffusion assay, a reliable method for assessing secondary metabolite antimicrobial efficacy. The study unveils the antimicrobial potential of the purified extract obtained from Lactiplantibacillus argentoratensis IT, isolated from goat milk. Notably, the AMP exhibited robust antibacterial activity against phytopathogens affecting solanaceous crops, including the Gram-negative Ralstonia solanacearum. Expression conditions and purification methods were optimized to identify the peptide's mass and sequence, utilizing LC-MS and SDS-PAGE. This paper underscores the application potential of Lactiplantibacillus spp. IT as a biocontrol agent for managing bacterial infectious diseases in plants. Results indicate optimal AMP production at 37°C, with a culture broth pH of 5 during fermentation. The obtained peptide sequence corresponded to peaks at 842.5 and 2866.4m/z ratio, with a molecular weight of approximately 5kDa according to tricine SDS-PAGE analysis. In conclusion, this study lays the foundation for utilizing Lactiplantibacillus spp. IT derived AMPs in plant biocontrol strategies, showcasing their efficacy against bacterial phytopathogens. These findings contribute valuable insights for advancing sustainable agricultural practices.

Application of Propolis Extracts in Prevention of the Occurrence and Development of Phytophthora infestans in Ecological Agricultural Production of Tomatoes (Solanum lycopersicum)

Organic Agricultural Production is a special system of food production that exists in a rule-based, socially demanding, and environmentally constrained space within wider agriculture. It must meet social standards in key areas, such as sustainable use of natural resources, while minimally impacting local ecosystems throughout the growth cycle. The use of phytopharmaceutical substitutes is a core component, replacing conventional agriculture pesticides which have been shown to damage local ecosystems. In recent years, considerable research effort has been put into discovering alternative natural substitutes with pesticidal and antifungal properties.
 The aim of this paper is to investigate the effects of propolis extracts on the growth and development of Phytopathological fungi, presenting an alternative to other phytopharmaceutical substitutes.
 In this paper, the “American” tomato species are used throughout as it represents a common supermarket tomato variety. The following are the conclusions central to this paper: (1) preventative usage of alcoholic extracts controlls the likelihood of development of Phytophthora infestans and its subsequent growth while having a reduced environmental impact (2) a comparison of propolis extracts with other staple organic extracts found improvements in profitability, produce growth speed and energy requirement (3) produce yield was increased with the use of a propolis solution compared to other organic extracts, however, a combined alcoholic extract of propolis was found to have further benefits, specifically in the prevention and neutralization of aphids.

Reply to Berry, C. Factors Related to Bacillus thuringiensis and Gut Physiology. Comment on "Rajan, V. An Alkaline Foregut Protects Herbivores from Latex in Forage, but Increases Their Susceptibility to Bt Endotoxin. Life 2023, 13, 2195".

The comment titled "Factors related to Bacillus thuringiensis and gut physiology" disputes some of the inferences in the paper "An Alkaline Foregut Protects Herbivores from Latex in Forage, but Increases Their Susceptibility to Bt Endotoxin" published in this journal. The key points in the dissent are the following: 1. Bt is generally safe to non-target species. 2. Transgenic Bt crops provide additional ecological benefits due to reductions in conventional pesticide use. 3. Susceptibility to Bt does not indicate alkalinity, nor vice versa. My response is summarized as follows: 1. Bt can form non-specific pores at concentrations of 100 ng/mL in culture, and so is potentially unsafe for animals with gut environments in which Bt persists at or above this level. 2. Initial reductions in insecticide applications have not been sustained and are even increasing in areas planted with transgenic Bt cotton. 3. Acidic guts degrade Bt more efficiently, but I concede that gut alkalinity does not imply susceptibility to Bt due to many factors including resistance in target species, toxin heterogeneity and variable modes of action. However, the susceptibility of foregut-fermenting herbivores with alkaline guts to Bt intoxication cannot be invalidated without further study.

Fungal Endophytes: Discovering What Lies within Some of Canada's Oldest and Most Resilient Grapevines.

Plant diseases and pests reduce crop yields, accounting for global crop losses of 30% to 50%. In conventional agricultural production systems, these losses are typically controlled by applying chemical pesticides. However, public pressure is mounting to curtail agrochemical use. In this context, employing beneficial endophytic microorganisms is an increasingly attractive alternative to the use of conventional chemical pesticides in agriculture. A multitude of fungal endophytes are naturally present in plants, producing enzymes, small peptides, and secondary metabolites due to their bioactivity, which can protect hosts from pathogens, pests, and abiotic stresses. The use of beneficial endophytic microorganisms in agriculture is an increasingly attractive alternative to conventional pesticides. The aim of this study was to characterize fungal endophytes isolated from apparently healthy, feral wine grapes in eastern Canada that have grown without agrochemical inputs for decades. Host plants ranged from unknown seedlings to long-lost cultivars not widely propagated since the 1800s. HPLC-MS was used to identify unique endophyte-derived chemical compounds in the host plants, while dual-culture competition assays showed a range in endophytes' ability to suppress the mycelial growth of Botrytis, which is typically controlled in viticulture with pesticides. Twelve of the most promising fungal endophytes isolated were identified using multilocus sequencing and morphology, while DNA barcoding was employed to identify some of their host vines. These fungal endophyte isolates, which consisted of both known and putative novel strains, belonged to seven genera in six families and five orders of Ascomycota. Exploring the fungal endophytes in these specimens may yield clues to the vines' survival and lead to the discovery of novel biocontrol agents.

Self-Assembly of a Dipeptide with a Reduced Amount of Copper into Antifungal and Antibacterial Particles.

With the growing concern over the environmental impact and health risks associated with conventional pesticides, there is a great need for developing safer and more sustainable alternatives. This study demonstrates the self-assembly of antimicrobial and antifungal spherical particles by a dipeptide utilizing a reduced amount of copper salt compared to the commonly employed formulation. The particles can be sprayed on a surface and form an antimicrobial coating. The effectiveness of the coating against the bacteria Pectobacterium brasiliense, a common pathogen affecting potato crops, was demonstrated, as the coating reduced the bacterial load by 7.3 log. Moreover, a comprehensive field trial was conducted, where the formulation was applied to potato seeds. Remarkably, it exhibited good efficacy against three prevalent potato pathogens (P. brasiliense, Pythium spp., and Spongospora subterranea) while demonstrating no phytotoxic effects on the potatoes. These findings highlight the tremendous potential of this formulation as a nonphytotoxic alternative to replace hazardous pesticides currently available in the market.

Nematocidal Potential of Phenolic Acids: A Phytochemical Seed-Coating Approach to Soybean Cyst Nematode Management.

Soybeans, one of the most valuable crops worldwide, are annually decimated by the soybean cyst nematode (SCN), Heterodera glycines, resulting in massive losses in soybean yields and economic revenue. Conventional agricultural pesticides are generally effective in the short term; however, they pose growing threats to human and environmental health; therefore, alternative SCN management strategies are urgently needed. Preliminary findings show that phenolic acids are significantly induced during SCN infection and exhibit effective nematocidal activities in vitro. However, it is unclear whether these effects occur in planta or elicit any negative effects on plant growth traits. Here, we employed a phytochemical-based seed coating application on soybean seeds using phenolic acid derivatives (4HBD; 2,3DHBA) at variable concentrations and examined SCN inhibition against two SCN types. Moreover, we also examined plant growth traits under non-infected or SCN infected conditions. Notably, 2,3DHBA significantly inhibited SCN abundance in Race 2-infected plants with increasingly higher chemical doses. Interestingly, neither compound negatively affected soybean growth traits in control or SCN-infected plants. Our findings suggest that a phytochemical-based approach could offer an effective, more environmentally friendly solution to facilitate current SCN management strategies and fast-track the development of biopesticides to sustainably manage devastating pests such as SCN.

INTEGRATED PEST MANAGEMENT STRATEGIES USING ENDOPHYTIC ENTOMOPATHOGENIC FUNGI

Insect pests harm crops severely and disperse a wide range of diseases that are transmitted by insects. Chemical pesticides are frequently used to manage them. Due to their constant usage over many years, insect pests have become increasingly resistant to practically all kinds of chemical pesticides, which has increased the demand for alternatives. For effective and environmentally safe insect pest control, insect pathogenic fungi are seen to be a viable alternative to practically all kinds of conventional pesticides. However, the viability of this strategy is being constrained by the sluggish death rate and necessity of large conidial concentrations. The ability of these fungi to regulate insects has previously been examined, but more recent research has focused on their potential to operate as plant endophytes to protect plants from phytopathogens and enhance other elements of agricultural output. The significance of these entomopathogenic fungi as endophytes in the context of biological control is discussed in this article. Finding local strains of entomopathogenic fungi that can colonise endophytes and their possible utility in the management of disease-causing pests are the main goals of our research for this review.

Policy options for promoting wider use of biopesticides in Thai agriculture

Biopesticides are rapidly growing in importance for crop protection globally, but nearly all growth is happening in high income countries. No previous work systematically analyzed how lower-income countries can better benefit from the increased availability of biopesticides, which is important because these countries are particularly affected by the adverse effects of chemical pesticide use. Here we review the legislation of biopesticides in Thailand and combine this with stakeholder interviews and interview data from 300 smallholder farmers producing rice, fruit, vegetables, and flowers. We find that Thailand has adopted a biopesticide registration system that facilitates a fast-track registration, but it is still relatively costly considering the small market size. While 65 % of the sampled farmers used biopesticides, most farmers still heavily relied on conventional pesticides as their main method to control pests. Education, farming experience, positive attitudes of biopesticides, adoption of other integrated pest management methods and contacts with government extension agents were positively associated with biopesticide use. Coordinated action is needed to stimulate the supply of a wider range of biopesticide products while promoting adoption among farmers.

Applying Ecology to Realize Organic Farming

Our conventional chemical fertilizers and pesticides are effective to improve our agricultural productivity, making our crops get more nutrients and less pests; however, the usage of our chemical fertilizers will lower quality of the soils, pesticides will also eliminate beneficial organisms which can fertilize soil and control pests. Pesticides except pyrethrin are hard to decay or be cleaned from the crops, they can be ingested by our human the most through our food chain and are harmful to human, pyrethrin is still harmful to fish. Organic farming doesn’t have these problems, but its productivity is still low, so we need organic methods to fertilize our crops and control harmful organisms that undermine our crops. Elements on the earth are used in cycle, so the only way to fertilize our crops is to make the elements move along the cycle, we can use methods that are same or similar to natural processes to provide fertilizers for our crops, such as producing ammonia by chemical synthesizing without adding other anions or cultivating clovers and processing them into organic nitrogen fertilizers, and import more sea foods into the inland and processing the inedible parts of them into organic fertilizers that can provide phosphorus, potassium and many other microelements that are scarce on the land. There are also many materials from some plants that can kill insects, they have small toxicity that is tolerable to human and can decompose after being used, such as matrine and nicotine. And it is also better to use natural enemies of the pest to control their population in low level, this is best to the crops since a low population of insects can stimulate the immunity of the crops by their bites, they possibly can also eat harmful microorganisms, practice shows the crops are less likely to be infected by diseases under such condition. It is perfect to use cat to eliminate mouse. By these organic methods to fertilize our crops and control harmful organisms, our organic farming possibly can have better productivity that is comparable to our conventional farming.

Smart controlled-release nanopesticides based on metal-organic frameworks.

The practical utilization rates of conventional pesticide formulations by target organisms are very low, which results in the pollution of ecological environments and the formation of pesticide residues in agricultural products. Water-based nanopesticide formulations could become alternative and effective formulations to eventually resolve the main issues of conventional pesticide formulations. In this feature article, we describe the design concept of smart (stimuli-responsive) controlled-release nanopesticides, which are created toward hierarchical targets (pests, pathogens, and foliage) in response to multidimensional stimuli from physiological and environmental factors (such as sunlight) of target organisms and plants, for achieving enhanced insecticidal and fungicidal efficacies. The pore sizes and functionalities of metal-organic frameworks (MOFs) can be fine-tuned through the choice of metal-containing units and organic ligands. Tailor-made MOF nanoparticles with large microporous or mesoporous sizes, as well as good biocompatibility and high thermal, mechanical, and chemical durabilities, are used to load pesticides within these pores followed by coating of plant polyphenols and natural polymers for stimuli-responsive controlled pesticide release. This feature article highlights our works on smart controlled-release MOF-based nanopesticides and also includes related works from other laboratories. The future challenges and promising prospects of smart controlled-release MOF-based nanopesticides are also discussed.

Green synthesis of (R)-3-hydroxy-decanoic acid and analogs from levoglucosenone: a novel access to the fatty acid moiety of rhamnolipids.

Rhamnolipids (RLs) are highly valuable molecules in the cosmetic, pharmaceutic, and agricultural sectors with outstanding biosurfactant properties. In agriculture, due to their potential to artificially stimulate the natural immune system of crops (also known as elicitation), they could represent a critical substitute to conventional pesticides. However, their current synthesis methods are complex and not aligned with green chemistry principles, posing a challenge for their industrial applications. In addition, their bioproduction is cumbersome with reproducibility issues and expensive downstream processing. This work offers a more straightforward and green access to RLs, crucial to decipher their mechanisms of action and design novel potent and eco-friendly elicitors. To achieve this, we propose an efficient seven-step synthetic pathway toward (R)-3-hydroxyfatty acid chains present in RLs, starting from cellulose-derived levoglucosenone, with Michael addition, Baeyer-Villiger oxidation, Bernet-Vasella reaction, and cross-metathesis homologation as key steps. This method allowed the production of (R)-3-hydroxyfatty acid chains and derivatives with an overall yield ranging from 24% to 36%.

Nano-Agrochemicals as Substitutes for Pesticides: Prospects and Risks.

This review delves into the mesmerizing technology of nano-agrochemicals, specifically pesticides and herbicides, and their potential to aid in the achievement of UN SDG 17, which aims to reduce hunger and poverty globally. The global market for conventional pesticides and herbicides is expected to reach USD 82.9 billion by 2027, growing 2.7% annually, with North America, Europe, and the Asia-Pacific region being the biggest markets. However, the extensive use of chemical pesticides has proven adverse effects on human health as well as the ecosystem. Therefore, the efficacy, mechanisms, and environmental impacts of conventional pesticides require sustainable alternatives for effective pest management. Undoubtedly, nano-agrochemicals have the potential to completely transform agriculture by increasing crop yields with reduced environmental contamination. The present review discusses the effectiveness and environmental impact of nanopesticides as promising strategies for sustainable agriculture. It provides a concise overview of green nano-agrochemical synthesis and agricultural applications, and the efficacy of nano-agrochemicals against pests including insects and weeds. Nano-agrochemical pesticides are investigated due to their unique size and exceptional performance advantages over conventional ones. Here, we have focused on the environmental risks and current state of nano-agrochemicals, emphasizing the need for further investigations. The review also draws the attention of agriculturists and stakeholders to the current trends of nanomaterial use in agriculture especially for reducing plant diseases and pests. A discussion of the pros and cons of nano-agrochemicals is paramount for their application in sustainable agriculture.

Degree of human activity exert differentiated influence on conventional and emerging pollutants in drinking water source.

Anthropogenic pollution poses a significant threat to drinking water sources worldwide. Previous studies have focused on the occurrence of pollutants in drinking water sources, but the impact of human activities on different types of pollutants in drinking water sources is still unclear. In this study, we chose the upper reaches of the Dongjiang River (URDR) as a casestudy to investigate the distribution characteristics of conventional pollutants, pesticides, and antibiotics along the gradient of human intervention. Our findings reveal that human activities can effect both conventional pollutants and emerging pollutants in the URDR to varying degrees. The escalation of human activities correlates with a rising trend in conventional pollutants, such as nitrogen (N) and phosphorus (P). Notably, only C1 (terrestrial humus) in dissolved organic matter (DOM) exhibits this increasing pattern. Pesticide and antibiotic concentrations are highest in areas with moderate and high levels of human activity, respectively, and the degree of eutrophication of drinking water closely follows the gradient of human activity. Our results also indicate that most pesticides pose a significant risk in the URDR, particularly pyrethroid pesticides (PYRs). Out of all antibiotics, only Norfloxacin (NFX) and Penicillin G (PENG) are classified as high-risk, with NFX exhibiting significant variation across different degrees of human activity. C1 and TP were the most important factors affecting the distribution of organophosphorus (OPPs) and PYRs, respectively. In conclusion, varying degrees of human activity exert differentiated influences on conventional and emerging pollutants in drinking water sources.

Sustainable Integrated Pest Management using Pheromones: Types, Synthesis, Mechanism of Action and Applications

Integrated pest management (IPM) strategies have been developed to combat the health, environmental and organismal adverse effects of conventional pesticides. It is possible to control agricultural and forestry pests by using insect pheromones. Recently, pheromone research has been influenced significantly by advances in agriculture as well as in technical aspects. Pheromone research is discussed in this review including synthesis, mechanism and application in integrated pest management. Moreover, the synthesis of certain chiral, racemic, monoolefinic and poly-olefinic pheromones has evolved a standard method for the manufacture of similar compounds. IPM is concluded with an in-depth discussion of pheromones' role in IPM. Further, it provides faster directions to organic chemists and entomologists in the development of eco-friendly tools. Future green agriculture will depend heavily on pheromones for its sustainability.

Microbial applications and agricultural sustainability: A simulation analysis of Dutch potato farms

CONTEXTFertilisers and plant protection products are essential for the economic viability of arable agriculture, but their overuse leads to environmental problems. Microbial applications have been proposed as a solution to reduce these environmental problems in arable farming. Experimental results suggest that microbial applications can increase yields and reduce abiotic stresses with fewer fertilisers and plant protection products. However, the overall effects of microbial applications on farm economics, the environment and social dimensions have not been quantified yet. OBJECTIVEIn this study, we assess the capacity of microbial applications to enhance the sustainability, including environmental, economic and social dimensions, of Dutch potato production. METHODSWe model a baseline scenario and a microbial application scenario with Monte Carlo simulation, and compare the scenarios using a composite sustainability index. The microbial application scenario is based on data from a Delphi expert elicitation. RESULTS AND CONCLUSIONSThe model indicates that, at present, microbial interventions do not contribute to the sustainability of Dutch potato production. In fact, the conventional baseline approach is more sustainable compared to the scenario involving microbial applications. In the microbial application scenario, cost per hectare of potato production is almost three times higher than in the baseline scenario, which are not covered by the 3.7% yield and 9.8% revenue increase. However, microbial applications can reduce CO2 emissions by 60% and active substances by 6.6%. Technological advancements are necessary to reduce costs per unit of production and increase environmental sustainability. SIGNIFICANCEThis study explores the impact of microbial applications on agricultural sustainability amid uncertainty, emphasising the need to quantify their effects. This study highlights the importance of economically viable sustainable practices to incentivise farmers' adoption. While efficient microbial applications can reduce reliance on conventional pesticides and fertilisers, they currently cannot contribute to the Farm-to-Fork reduction goals. Future research should focus on cost-effective microbial applications for disease prevention. We provide four routes for further research on microbial applications.

Electrophysiological and behavioural responses of Plutella xylostella L. (Lepidoptera: Plutellidae) to thirteen non-host plant essential oils

The diamondback moth (DBM), Plutella xylostella (L.), is a cosmopolitan obligate pest of cruciferous crops. Currently, DBMs management is largely dependent on broad-spectrum synthetic pesticides, which has led to the adverse effects on the environment, human health, and nontargeted organisms. Thus, alternative control methods are needed. The essential oils (EOs) derived from bioactive species may be developed as effective alternatives for the management of DBMs that is safe and eco-sustainable than conventional pesticides. In this study, we investigated electrophysiological (EAG) and behavioral responses of DBM adults to the thirteen non-host EOs of Acorus calamus, Ageratum conyzoides, Artemisia argyi, Chenopodium ambrosioides, Cymbopogon citratus, Foeniculum vulgare, Ocimum basilicum, Pelargonium hortorum, Perilla frutescens, Pogostemon cablin, Polygonum hydropiper, Rosmarinus officinalis, and Ruta graveolens in order to contribute to the development of low environmental impact management alternatives. EAG recordings revealed all the tested EOs significantly elicited EAG responses of DBM females, and the males were sensitive to the eleven EOs except A. conyzoides and O. basilicum. Meanwhile, EAG recordings of DBMs exhibited dose-dependent responses to these tested EOs in most cases. In Y-tube olfactometer bioassays, the EOs of A. calamus, C. citratus, P. hortorum, P. hydropiper, and R. graveolen demonstrated prominent repellent effects on DBM females at concentrations of 10 μg/μL or higher. The results of oviposition bioassays found the number of eggs on the two plants with the five tested EOs were less than that on the two plants with paraffin oil. And the oviposition indexes of the plants that fixed with the EOs of P. hortorum, R. graveolen, A. calamus, P. hydropiper, C. citratus, and paraffin oil were –71.81%, –59.43%, –57.46%, –51.11%, –35.41%, and 0.09%, respectively. These findings indicate that the five EOs, especially P. hydropiper EO, provide active and safe tools for natural repellents to prevent and control DBMs infestations of cruciferous vegetables.

Prediction of Oxygen Distribution in Silos and Chambers Filled with Various Agricultural Commodities

In the context of post-harvest pest management in agricultural products, the adoption of modified atmospheres presents an eco-friendly alternative to conventional pesticides. This study focuses on nitrogen gas as a potential agent for insect control in stored commodities, utilizing computational simulations (by employing the convection–diffusion equation) to investigate its penetration and distribution within two common storage configurations: chamber-contained pallets and silos. The results highlight the influence of boundary conditions, commodity porosity, and convection effects on nitrogen dispersion. In chamber scenarios, the first boundary condition considers that pallets are placed inside a chamber with uniform (99.5%) nitrogen concentration, whereas in the second one, the concentration gradually increases from 78% to 99.5%. The average duration required for O2 concentration to reach 1% is approximately 10.7 h and 133.3 h for the two boundary conditions, respectively. Among the agricultural commodities, walnuts (kernels) exhibit the shortest duration, while prunes require the longest time. In silos, convection and diffusion interact to establish a consistent diffusion layer thickness. Most agricultural products exhibit similar behavior, with average times of 13.5 h, 25.4 h, and 37.0 h for three heights (10 m, 20 m, and at the silo’s top at 30 m), respectively.

Borrelidin-producing and root-colonizing Streptomyces rochei is a potent biopesticide for two soil-borne oomycete-caused plant diseases

Biopesticides are an attractive biotechnological alternative to conventional pesticides for soil-borne plant diseases. A screening strategy with over 100 actinomycetes bacteria isolated from diverse rhizosphere soils uncovered the Streptomyces rochei strain JK1 as a potent inhibitor of oomycete growth. The culture filtrates of the JK1 strain inhibited oomycete growth in plate assays and could suppress two major oomycete-caused plant diseases caused by Pythium myriotylum and Phytophthora sojae. The macrolide secondary metabolite borrelidin was identified using HR-ESI-MS and NMR from growth-inhibitory fractions and inhibited both oomycete growth and plant diseases. The biosynthetic gene clusters in the genome of S. rochei JK1 show the potential to produce other secondary metabolites as well as borrelidin. The JK1 biosynthetic gene clusters are partly conserved among the publicly available S. rochei genomes, whereby each JK1 cluster was shared with at least one of eight other S. rochei strains. The S. rochei JK1 strain, which was isolated from the rhizosphere of soybean plants, colonized soybean roots as well as ginger roots suggesting competence in diverse rhizospheres. The biotechnological application of the strain and fermentation products is emphasized by how the oomycete growth inhibition of the culture filtrate was stable across a range of temperature and pH levels. The genomic, and metabolite data, mechanistic-insights into disease control, and the range of oomycete-caused diseases controlled, all support the S. rochei JK1 strain as an important new bioresource.