Agricultural Pest Management: The Role of Microorganisms in Biopesticides and Soil Bioremediation

Silva Júnior A.H., Silva de Oliveira C.R., Leal T.W., Mapossa A.B., Fiates J., Ulson de Souza A.A., Ulson de Souza S.M., da Silva A.

Organochlorine pesticides have been widely used in agriculture to control agricultural pests. Although effective in controlling pests, organochlorine pesticides present numerous hazards to ecosystems and human health due to their persistence in the environment, bioaccumulation, and toxicity. Scientific studies have shown that organochlorines may be associated with endocrine and neurological problems. Several strategies have been developed to apply treatment techniques to remove pesticides from various ecosystems, both aquatic and terrestrial. Physicochemical and biological methods have revealed other potentialities for remediation of aqueous environments contaminated with organochlorine pesticides. In addition, combined processes using different approaches have been highlighted as efficient alternatives to mitigate the impacts of agrochemicals on the environment, e.g., physical technique followed by a biological process. However, there are still numerous gaps that need to be explored and elucidated. Therefore, this review addressed the impacts of organochlorine pesticides on ecosystems and some treatment techniques used to remove agrochemicals from water. Furthermore, new findings, technological perspectives, and opportunities on this subject were presented and discussed.

Wared Musa H.A., Abass M.H., Al-Farttoosy A.H.

Abstract Pesticides are used all over the world in agricultural operations to reduce the damage of pests and to improve the productivity of agricultural crops. The excessive use of these chemical compounds has led to the deterioration of soil and increase the level of pollution of water and air resources. Moreover, the continuous use and non-target toxicity of pesticides has become a major concern to the agricultural ecosystem that directly hinders the productivity of agricultural products. Therefore, this study aimed to isolate and identify fungal and bacterial species with the ability to biodegrade fungicide via conducting preliminary tests to find out which of them have the ability to grow in a treated medium with a fungicide Difenoconazole, which belongs to the group of the pesticides Triazoles. The fungi and bacteria that succeeded in growing were as follow Aspergillus flavus, Aspergillus ochraceus, Bacillus cereus S1 and Bacillus cereus S2 were identified by extracting their genomic DNA and applying the primers ITS and 16s rRNA for both examined fungi and bacteria, respectively. The fungi were laboratory adapted to multiple concentrations reaching the highest concentration of 550 mgL-1, while bacteria reached 1200 mgL-1 laboratory to break down the pesticide. The results of the combinations tested as the B. cereus S1 and B. cereus S2 were the fastest growing in the liquid medium PDB at the concentration of 325 mgL-1. While the combination A. flavus and B. cereus S1 had the highest biodegrading ability at the same concentration, which led to the disappearance of the pesticide Difenoconazole turbidity in the liquid medium as a result of its consumption by fungal and bacterial isolates. As for the treatment of the pesticide in the solid PDA medium to know its effect on the growth of fungi and the formation of spores, the results revealed that fungal isolates increase their vegetative growth when the concentration increases, the production of fungal spores decreases, and indicates the ability of the fungi to use the pesticide as an energy source.

Rahman H., Ahmad I., Jon P.H., Salam A., Rabbi M.F.

AbstractGlobally, tea production and its quality fundamentally depend on tea leaves, which are susceptible to invasion by pathogenic organisms. Precise and early-stage identification of plant foliage diseases is a key element in preventing and controlling the spreading of diseases that hinder yield and quality. Image processing techniques are a sophisticated tool that is rapidly gaining traction in the agricultural sector for the detection of a wide range of diseases with excellent accuracy. This study focuses on a pragmatic approach for automatically detecting selected tea foliage diseases based on convolutional neural network (CNN). A large dataset of 3330 images has been created by collecting samples from different regions of Sylhet division, the tea capital of Bangladesh. The proposed CNN model is developed based on tea leaves affected by red rust, brown blight, grey blight, and healthy leaves. Afterward, the model’s prediction was validated with laboratory tests that included microbial culture media and microscopic analysis. The accuracy of this model was found to be 96.65%. Chiefly, the proposed model was developed in the context of the Bangladesh tea industry.

Jangra S., Chinnaiah S., Patil S.R., Shukla B., Devendran R., Kumar M.

Insect-transmitted plant viruses are a major threat to global agricultural crop production. Receptors play a prominent role in the interplay between host-pathogen and vector interaction. The virus–vector relationship involves both viral and vector receptors. Receptors-like kinases (RLKs) and receptor-like proteins play a crucial role in plant immunity, which acts as a basal defense. Pathogens can evade or block host recognition by their effector proteins to inhibit pathogen recognition receptor (PRR)-mediated signaling. Intriguingly, RLKs are also known to interact with viral proteins and impact plant susceptibility against viruses, while the endocytic receptors in vectors assist in the binding of the virus to the vectors. Unlike other receptors of fungi and bacteria which have three different domains located from extracellular or intracellular to perceive a multitude of molecular patterns, the characterization of viral receptors is quite complex and limited since the virus is directly injected into plant cells by insect vectors. Little is known about these receptors. Unraveling the receptors involved in virus entry and transmission within the vector will provide vital information in virus–vector interactions. This review focuses on efforts undertaken in the identification and characterization of receptors of plant viruses within the host and vector. This will lead to a better understanding of the cellular mechanism of virus transmission and spread, and further suggests new alternative tools for researchers to develop an integrated approach for the management of viral diseases and associated vectors.

Orfei B., Moretti C., Scian A., Paglialunga M., Loreti S., Tatulli G., Scotti L., Aceto A., Buonaurio R.

Abstract Bacterial plant diseases are difficult to control as the durability of deployed control measures is thwarted by continuous and rapid changing of bacterial populations. Although application of copper compounds to plants is the most widespread and inexpensive control measure, it is often partially efficacious for the frequent appearance of copper-resistant bacterial strains and it is raising concerns for the harmful effects of copper on environment and human health. Consequently, European Community included copper compounds in the list of substances candidates for substitution. Nanotechnologies and the application of nanoparticles seem to respond to the need to find new very effective and durable measures. We believe that Argirium-SUNCs®, silver ultra nanoclusters with an average size of 1.79 nm and characterized by rare oxidative states (Ag2+/3+), represent a valid candidate as a nano-bactericide in the control of plant bacterial diseases. Respect to the many silver nanoparticles described in the literature, Argirium-SUNCs have many strengths due to the reproducibility of the synthesis method, the purity and the stability of the preparation, the very strong (less than 1 ppm) antimicrobial, and anti-biofilm activities. In this mini-review, we provide information on this nanomaterial and on the possible application in agriculture. Key points • Argirium-SUNCs have strong antimicrobial activities against phytopathogenic bacteria. • Argirium-SUNCs are a possible plant protection product. • Argirium-SUNCs protect tomato plants against bacterial speck disease. Graphical Abstract

Karamchandani B.M., Dalvi S.G., Bagayatkar M., Banat I.M., Satpute S.K.

Chemical pesticides, fungicides, fertilizers, and high-breeding crop varieties are normally used to enhance crop productivity worldwide. Nevertheless, overuse and persistence of these chemicals has negative effects on soil, water, and air, disrupting the food chain and the ecosystem. Recent advances in nanotechnology, particularly for the agriculture sector are being explored in crop production and protection with particular focus on nano-pesticides, nano-fertilizers, nano-biosensors, nano-devices as remediation strategies to deal with toxic effects of chemicals. The efficiency and fate of nanomaterials are heavily influenced by their properties and interactions with soil constituents. Chitosan (CH) and chitosan nanoparticles (CHNPs) are the remarkable due to their exceptional structural and functional properties including antimicrobial potential against several phytopathogens (feed, food, cereals, fibre, oil, industrial, medicinal, ornamental crops). CH and CHNPs can be applied individually and/or in combinations with other active components to manage plant diseases. This review highlights the role of CH and CHNPs in the defence mechanisms in plants and other promising agricultural applications. It also presents information on fungal chitosan (FCH) along with its promising functional properties over the CH of crustacean origin and strategies employed for the preparation of NPs-based (CHNPS or FCHNPs) formulations. Biosynthesis of CHNPs or FCHNPs using CH or FCH is also described briefly. Information on the patents granted for CH and CHNPs in the agriculture sector is included. The role of other additives like surface active or wetting agents, dispersants, UV protectants in designing the powerful agro-nano-formulations for future development of a sustainable nano-enabled agriculture practices are described.

Eddleston M.

Amaral I., Antunes S.C., Rebelo D., Carvalho A.P., Rodrigues S.

Biopesticides are natural compounds considered more safe and sustainable for the environment. Spinosad (SPI) is a bioinsecticide used in marketed worldwide, to eradicate a variety of pests. This study aimed to assess the impacts of the SPI on the non-target organism zebrafish (Danio rerio). Several concentrations of SPI were tested to evaluate the acute (0.07-1.0 mg/L) and chronic (0.006-0.100 mg/L) ecotoxicological effects. To evaluate sub-individual effects, antioxidant defense, lipid peroxidation, energy sources, and cholinergic biomarkers were quantified. In both exposures, SPI induced significant effects on antioxidant defense indicating oxidative stress, disrupting energy pathways, and exhibiting neurotoxic effects, under environmentally relevant conditions. Integrated Biomarker Response (IBRv2) showed that with increasing SPI concentrations, an increase in impacts on organisms was recorded. This study demonstrates the vulnerability of a non-target organism to SPI, a bioinsecticide considered environmentally safe. Further research is essential to fully understand the implications of spinosad to aquatic biota.

Karthi S., Vasantha-Srinivasan P., Senthil-Nathan S., Han Y.S., Shivakumar M.S., Murali-Baskaran R.K., Kalaivani K., Radhakrishnan N., Park K.B., Malafaia G.

Entomopathogenic fungi, particularly Metarhizium and Beauveria species, are emerging as effective biocontrol agents for combating lepidopteran pests in agricultural and forestry settings. This review provides a comprehensive overview of their modes of action, secondary metabolites, extracellular enzymes, and infection mechanisms. These fungi employ various strategies, including the secretion of proteolytic enzymes, chitinolytic enzymes, esterases, and lipases, to penetrate the insect cuticle and initiate infection. The process involves spore recognition, adhesion, germination, and differentiation into infective structures. The impact of fungal strains on the insect immune system and the commercial availability of fungal pesticides are also discussed. Furthermore, the advancements in genetically engineered mycotoxins and the key challenges facing their implementation are addressed, in addition to listing future research directions. This review offers valuable insights for researchers involved in the development and application of entomopathogenic fungi for sustainable pest management practices.

Wend K., Zorrilla L., Freimoser F.M., Gallet A.

AbstractPlant protection measures are necessary to prevent pests and diseases from attacking and destroying crop plants and to meet consumer demands for agricultural produce. In the last decades the use of chemical pesticides has largely increased. Farmers are looking for alternatives. Biopesticides should be considered a sustainable solution. They may be less toxic than chemical pesticides, be very specific to the target pest, decompose quickly, and be less likely to cause resistance. On the other hand, lower efficacy and higher costs are two disadvantages of many biopesticides. Biopesticides include macroorganisms, natural compounds and microorganisms. Microbial pesticides are the most widely used and studied class of biopesticides. The greatest difference between microbial and chemical pesticides is the ability of the former to potentially multiply in the environment and on the crop plant after application. The data requirements for the European Union and the United States Environmental Protection Agency are highlighted, as these regulatory processes are the most followed in regions where local regulations for biopesticide products are not available or vague. New Approach Methods already proposed or harmonized for chemical pesticides are presented and discussed with respect to their use in evaluating microbial pesticide formulations. Evaluating the microbials themselves is not as simple as using the same validated New Approach Methods as for synthetic pesticides. Therefore, the authors suggest considering New Approach Method strategies specifically for microbials and global harmonization with acceptability with the advancements of such approaches. Further discussion is needed and greatly appreciated by the experts.

Khalaf A., Francis O., Blaxter M.L.

AbstractMicrosporidia and Apicomplexa are eukaryotic, single‐celled, intracellular parasites with huge public health and economic importance. Typically, these parasites are studied separately, emphasizing their uniqueness and diversity. In this review, we explore the huge amount of genomic data that has recently become available for the two groups. We compare and contrast their genome evolution and discuss how their transitions to intracellular life may have shaped it. In particular, we explore genome reduction and compaction, genome expansion and ploidy, gene shuffling and rearrangements, and the evolution of centromeres and telomeres.

Huang Y., Li Z.

Pesticides are widely used in agriculture, but their impact on the environment and human health is a major concern. While much attention has been given to their presence in soil, water, and food, there have been few studies on airborne pesticide pollution on a global scale. This study aimed to assess the extent of atmospheric pesticide pollution in countries worldwide and identify regional differences using a scoring approach. In addition to analyzing the health risks associated with pesticide pollution, we also examined agricultural practices and current air quality standards for pesticides in these countries. The pollution scores varied significantly among the countries, particularly in Europe. Asian and Oceanic countries generally had higher scores compared to those in the Americas, suggesting a relatively higher level of air pollution caused by pesticides in these regions. It is worth noting that the current pollution levels, as assessed theoretically, pose minimal health risks to humans. However, studies in the literature have shown that excessive exposure to pesticides present in the atmosphere has been associated with various health problems, such as cancer, neuropsychiatric disorders, and other chronic diseases. Interestingly, European countries had the highest overall pesticide application intensities, but this did not necessarily correspond to higher atmospheric pesticide pollution scores. Only a few countries have established air quality standards specifically for pesticides. Furthermore, pollution scores across states in the USA were investigated and the global sampling sites were mapped. The findings revealed that the scores varied widely in the USA and the current sampling sites were limited or unevenly distributed in some countries, particularly the Nordic countries. These findings can help global relevant environmental agencies to set up comprehensive monitoring networks. Overall, the present research highlights the need to create a pesticide monitoring system and increase efforts to enhance pesticide regulation, ensure consistency in standards, and promote international cooperation.

Lu T., Lei C., Gao M., Lv L., Zhang C., Qian H., Tang T.

Pesticides play a vital role in ensuring modern agricultural production, but also adversely affecting soil health. Microorganisms are the cornerstone of soil ecology, however, to date, there are few unified standards to measure the risk of soil pesticide residues to soil microbial community. To compensate for this gap, we collected soil samples from 55 orchards and monitored and risk-assessed 165 pesticides to microbial community in the soil. Results showed that a total of 137 pesticides were detected in all samples. Pesticide residues significantly influenced the microbial diversity and community structure in orchard soils, particularly fungicides and herbicides. The risk entropy of each pesticide was calculated in all samples and it was found that 60% of the samples had a "pesticide risk" (Risk quotient > 0.01), where the relative abundance significantly increased in 43 genera and significantly decreased in 111 genera (p < 0.05). Through multiple screens, we finally identified Bacillus and Sphingomonas as the most abundant sensitive genera under pesticide perturbation. The results showed that despite the complexity of the effects of pesticide residues on soils health, we could reveal them by identifying changes in soil bacterial, especially by the differences of microbial biomarkers abundance. The present study could provide new insights into the research strategy for pesticide pollution on soil microbial communities. ENVIRONMENTAL IMPLICATION: The risk of pesticide residues in soil needs to be quantified and standardized. We believe that microorganisms can be used as a marker to indicate soil pesticide residue risk. For this end, we investigated the residues of 165 pesticides in 55 orchard soil samples, calculated pesticide risk entropy and their effects on the soil microbial community. Through multiple analyzing and screening, we ultimately identified that, out of the 154 detected biomarkers, Bacillus and Sphingomonas were the most abundant sensitive genera under pesticide perturbation, which have the potential to be used as key biomarkers of soil microbiomes induced by pesticide perturbation.

Doolotkeldieva T., Konurbaeva M., Bobusheva S.

Makgoba L., Abrams A., Röösli M., Cissé G., Dalvie M.A.

Abstract Dichlorodiphenyltrichloroethane (DDT) usage has been prohibited in developed nations since 1972 but is exempted for use in indoor residual spraying (IRS) in developing countries, including African countries, for malaria control. There have been no previous reviews on DDT residues in water resources in Africa. The study aimed to provide a review of available research investigating the levels of DDT residues in water sources in Africa and to assess the consequent human health risks. A scoping review of published studies in Africa was conducted through a systematic electronic search using PubMed, Web of Science, EBSCO HOST, and Scopus. A total of 24 articles were eligible and reviewed. Concentrations of DDT ranged from non-detectable levels to 81.2 μg/L. In 35% of the studies, DDT concentrations surpassed the World Health Organization (WHO) drinking water guideline of 1 μg/L in the sampled water sources. The highest DDT concentrations were found in South Africa (81.2 μg/L) and Egypt (5.62 μg/L). DDT residues were detected throughout the year in African water systems, but levels were found to be higher during the wet season. Moreover, water from taps, rivers, reservoirs, estuaries, wells, and boreholes containing DDT residues was used as drinking water. Seven studies conducted health risk assessments, with two studies identifying cancer risk values surpassing permissible thresholds in water sampled from sources designated for potable use. Non-carcinogenic health risks in the studies fell below a hazard quotient of 1. Consequently, discernible evidence of risks to human health surfaced, given that the concentration of DDT residues surpassed either the WHO drinking water guidelines or the permissible limits for cancer risk in sampled drinking sources within African water systems. Therefore, alternative methods for malaria vector control should be investigated and applied.

Meng S., Liang C., Zheng Q., Zhu S., Wu J., Wang B., Wang Y., Zhang Z., Cheng D.

Khaskheli M.A., Nizamani M.M., Tarafder E., Das D., Nosheen S., Muhae-Ud-Din G., Khaskheli R.A., Ren M., Wang Y., Yang S.

Sorghum (Sorghum bicolor L.) is a globally important energy and food crop that is becoming increasingly integral to food security and the environment. However, its production is significantly hampered by various fungal phytopathogens that affect its yield and quality. This review aimed to provide a comprehensive overview of the major fungal phytopathogens affecting sorghum, their impact, current management strategies, and potential future directions. The major diseases covered include anthracnose, grain mold complex, charcoal rot, downy mildew, and rust, with an emphasis on their pathogenesis, symptomatology, and overall economic, social, and environmental impacts. From the initial use of fungicides to the shift to biocontrol, crop rotation, intercropping, and modern tactics of breeding resistant cultivars against mentioned diseases are discussed. In addition, this review explores the future of disease management, with a particular focus on the role of technology, including digital agriculture, predictive modeling, remote sensing, and IoT devices, in early warning, detection, and disease management. It also provide key policy recommendations to support farmers and advance research on disease management, thus emphasizing the need for increased investment in research, strengthening extension services, facilitating access to necessary inputs, and implementing effective regulatory policies. The review concluded that although fungal phytopathogens pose significant challenges, a combined effort of technology, research, innovative disease management, and effective policies can significantly mitigate these issues, enhance the resilience of sorghum production to facilitate global food security issues.

Ríos-Ruiz W.F., Jave-Concepción H.G., Torres-Chávez E.E., Rios-Reategui F., Padilla-Santa-Cruz E., Guevara-Pinedo N.E.

This article presents a systematic review of the ecophysiological mechanisms underpinning the essential role of plant-growth-promoting microorganisms (PGPMs) in improving rice yield and quality. The scientific literature is thoroughly reviewed, highlighting how PGPMs positively influence the growth, development, and health of rice plants. Key aspects, such as nitrogen fixation, nutrient solubilization, hormone production, and disease resistance induction, are emphasized. Additionally, technological advancements related to PGPM use are analyzed, including the identification of effective strains, the formulation of enhanced biofertilizers, and genetic engineering. The article concludes that PGPMs represent a promising tool with which to boost the sustainability and productivity of rice cultivation, providing a robust foundation for future research and practical applications in a field crucial to global food security.

Xu W., Wang Y., Zhu M., Yu S., Qin T., Zhu S., Yin Z.

De Silva A.G., Hashim Z.K., Solomon W., Zhao J., Kovács G., Kulmány I.M., Molnár Z.

Agricultural soil has great potential to address climate change issues, particularly the rise in atmospheric CO2 levels. It offers effective remedies, such as increasing soil carbon content while lowering atmospheric carbon levels. The growing interest in inoculating soil with live microorganisms aims to enhance agricultural land carbon storage and sequestration capacity, modify degraded soil ecosystems, and sustain yields with fewer synthetic inputs. Agriculture has the potential to use soil microalgae as inoculants. However, the significance of these microorganisms in soil carbon sequestration and soil carbon stabilization under field conditions has yet to be fully understood. Large-scale commercial agriculture has focused on the development and use of inoculation products that promote plant growth, with a particular emphasis on enhancing yield attributes. Gaining more profound insights into soil microalgae’s role in soil carbon cycling is necessary to develop products that effectively support soil carbon sequestration and retention. This review comprehensively explores the direct and indirect mechanisms through which soil microalgae contribute to soil carbon sequestration, highlighting their potential as microbial inoculants in agricultural settings. This study underlines the need for more research to be conducted on microalgae inoculation into agricultural soil systems aimed at mitigating carbon emissions in the near future.

Santos W.M., Martins L.D., Bezerra A.C., Souza L.S., Jardim A.M., Silva M.V., Souza C.A., Silva T.G.

With the growing demand for efficient solutions to face the challenges posed by population growth and climate change, the use of unmanned aerial vehicles (UAVs) emerges as a promising solution for monitoring biophysical and physiological parameters in forage crops due to their ability to collect high-frequency and high-resolution data. This review addresses the main applications of UAVs in monitoring forage crop characteristics, in addition to evaluating advanced data processing techniques, including machine learning, to optimize the efficiency and sustainability of agricultural production systems. In this paper, the Scopus and Web of Science databases were used to identify the applications of UAVs in forage assessment. Based on inclusion and exclusion criteria, the search resulted in 590 articles, of which 463 were filtered for duplicates and 238 were selected after screening. An analysis of the data revealed an annual growth rate of 35.50% in the production of articles, evidencing the growing interest in the theme. In addition to 1086 authors, 93 journals and 4740 citations were reviewed. Finally, our results contribute to the scientific community by consolidating information on the use of UAVs in precision farming, offering a solid basis for future research and practical applications.