Advances in stimuli-responsive systems for pesticides delivery: Recent efforts and future outlook

Delivery of Hexaconazole by the Carboxymethylcellulose grafting and Cellulase/pH responsiveness hollow mesoporous silica nanoparticles

Conventional pesticides are easily lost, and poorly targeted deposition causes pollution and economic losses because of their large particle sizes. Cellulase/pH Responsiveness Hollow Mesoporous Silica Nanoparticles (Hex/HMSN-CMC) was developed to respond rapidly to changes in the environment. The particle size of Hex/HMSN-CMC was 133.44 nm. The characterization results confirmed the introduction of CMC and a Hex loading capacity of 12 %. Controlled-release kinetics indicated that the drug-loaded system could exhibit specific responses to pH and cellulase, with the cumulative release rate exceeding 80 %. Bioactivity assays showed that the EC₅₀ values of Hex/HMSN nanoparticles and the commercial hexaconazole suspension against Rhizoctonia solani were 0.638 mg/L and 1.281 mg/L at 5 days, and 1.404 mg/L and 2.454 mg/L at 10 days after application, respectively. Furthermore, Hex/HMSN-CMC demonstrated the ability to transport within mycelium and rice plants. Contact angle experiments showed that the wetting ability increased with the introduction of CMC. Additionally, Hex/HMSN-CMC increased rice seed germination than Hex alone. Zebrafish toxicity assays indicated the LC₅₀ value of Hex/HMSN-CMC to zebrafish was increased by 16.65 % compared with Hex SC. These results indicate hexaconazole delivery system with dual responsiveness to pH and cellulase could achieve targeted transportation and reduce pesticide runoff.

Nanocellulose-hydrogel hybrids: A review on synthesis and applications in agriculture, food packaging and water remediation

The growing demand for sustainable and environment-friendly materials has driven extensive research on biopolymers for applications in agriculture, food science, and environmental remediation. Among these, nanocellulose-hydrogel hybrids (NC-HHs) have gained significant attention as an innovative class of bio-based materials that uniquely combine the remarkable physicochemical properties of nanocellulose with the functional versatility of hydrogels. These hybrids are characterised by exceptional water retention, mechanical strength and biodegradability, enabling advances in precision agriculture, smart food preservation and contaminant remediation. This review provides a comprehensive understanding of the synthesis, properties, and multifunctional applications of NC-HHs, emphasising their innovative role in sustainability. In agriculture, NC-HHs enhance soil moisture retention, support plant growth, and serve as carriers for controlled-release fertilizers, optimizing water and nutrient use efficiency. In the food industry, they enable intelligent packaging solutions that extend shelf life, monitor food freshness, and inhibit microbial growth. Additionally, NC-HHs present groundbreaking strategies for environmental remediation by effectively immobilizing pollutants in water and soil. Beyond summarizing recent advances, this review presents an in-depth mechanistic perspective on the interactions between NC and HH, critically evaluating their structure-property relationships, functional adaptability and application-specific performance. By integrating recent advances in nanocellulose functionalisation, polymer chemistry and the development of responsive hydrogels, this review critically examines the key technological innovations and future prospects of NC-HHs, underscoring their transformative potential in addressing global challenges related to food security, environmental sustainability, and sustainable agricultural practices.

Sodium-lignosulfonate-conjugated metal-organic frameworks as dual-stimulus-responsive carriers for improved pesticide targeting

The use of intelligent pesticides that respond to environmental stimuli is a promising strategy for achieving sustainable pest control while mitigating pesticide-related environmental pollution. This study reports the design of a pH and laccase dual-stimulus-responsive pesticide-slow-release composite (IMI@UiO-66@SL). The composite utilises an imidacloprid (IMI)-encapsulated metal-organic framework (MOF; UiO-66) as a nano-carrier and sodium lignosulfonate (SL) as a capping agent. Results show that IMI@UiO-66@SL exhibits excellent IMI release properties in acidic and laccase-rich environments, which closely mimic the physiological and behavioural conditions of termites. Furthermore, compared to the original IMI formulation, IMI@UiO-66@SL exhibits enhanced and prolonged insecticidal activity. Briefly, this study reports a promising approach for the sustainable management of termite colonies.

Bimetallic MOF-Based Hybrid Platform with Dual Stimuli-Responsiveness for Sustained Release and Enhanced Retention

Pesticide delivery carriers provide protection against pathogens but face significant challenges, including limited loading capacity, rapid release rates, and inconsistent performance. To address these issues, this study develops a dual-stimuli-responsive pesticide delivery carrier, featuring an iron-copper bimetal-organic framework (Fe-Cu MOF) supported on diatomaceous earth (DE) and coated with lauric acid (LA). Here, DE serves as a biocompatible scaffold, enhancing the adhesion and retention of MOF particles at target sites, thereby improving the pesticide localization and delivery efficiency. The carrier exhibits a high thiabendazole (Tbz) loading capacity of 38.14% owing to its nanoporous structure. The LA coating functions as a pH- and temperature-responsive barrier, regulating pesticide release to prolong the treatment duration and minimizing the need for repeated applications. The carrier demonstrates controlled release rates of 80.73% at pH 5 and 96.55% at 40 °C, confirming its dual-stimuli responsiveness. In vitro assays reveal 92.26% inhibition of Botrytis cinerea at 1 μg mL-1, while in vivo experiments on tomato plants and fruits show complete inhibition at 200 μg mL-1. Additionally, the developed composites adhere strongly to leaves through electrostatic and hydrogen-bonding interactions, reducing the loss of pesticide due to rain erosion. Overall, DE-MOF-Tbz-LA presents a promising and efficient alternative to conventional pesticide applications.

A simple approach to fabricate chitosan-delivered avermectin controlled release microparticles for improved efficacy and reduced residues

The presence of a synergistic effect between carrier and insecticide in controlled release formulations is highly desirable to improve efficacy to target pests and reduce insecticide use. Herein, controlled release microparticles of avermectin (AVM) were fabricated using natural chitosan (CTS) as a carrier by a pH adjustment method. The resulted AVM@CTS microparticles displayed high encapsulation efficiency (73.3 %), outstanding photostability, obvious pH/temperature sensitivity, and good deposition behavior on Chinese cabbage leaves. Instrument detections in combination with molecular dynamics simulations showed that AVM interacted with CTS mainly through physical adsorption, adhesion, and weak H-bonds. In vitro release data of the controlled release formulation obeyed the first-order kinetic equation. Toxicity tests exhibited a significantly synergistic effect between CTS and AVM, resulting in better quick-acting and long-term efficacy against Plutella xylostella larvae than that of the AVM acetone solution. The 72 h LC50 of the formulation for a 21-day efficacy was 12.73 mg/L, much lower than the value (31.53 mg/L) of the AVM solution. Moreover, the AVM@CTS microparticles exhibited shorter half-life (19.6 days) than the unformulated AVM (23.0 days) under natural conditions in soil. This work contributes to the development of controlled release system with carrier-insecticide synergistic effect for sustainable pest control.

The application of machine learning in 3D/4D printed stimuli-responsive hydrogels

The integration of machine learning (ML) in materials fabrication has seen significant advancements in recent scientific innovations, particularly in the realm of 3D/4D printing. ML algorithms are crucial in optimizing the selection, design, functionalization, and high-throughput manufacturing of materials. Meanwhile, 3D/4D printing with responsive material components has increased the vast design flexibility for printed hydrogel composite materials with stimuli responsiveness. This review focuses on the significant developments in using ML in 3D/4D printing to create hydrogel composites that respond to stimuli. It discusses the molecular designs, theoretical calculations, and simulations underpinning these materials and explores the prospects of such technologies and materials. This innovative technological advancement will offer new design and fabrication opportunities in biosensors, mechatronics, flexible electronics, wearable devices, and intelligent biomedical devices. It also provides advantages such as rapid prototyping, cost-effectiveness, and minimal material wastage.

Controlled Release of Hydrophilic Drug from Hollow Nanodots

Here the challenge of limited encapsulation efficiency of ionizable hydrophilic molecules in silica materials is addressed. Two effective strategies are showcased that allow high encapsulation efficiency of salicylic acid, while simultaneously maintaining the morphology and particle size of silica nanocapsules. These promising approaches involve the formation and encapsulation of a prodrug or the complexation of the hydrophilic payload with a hydrophobic moiety to form a complex that is dissociated in acidic conditions. Well-defined core-shell silica nanocapsules with a diameter of 6 nm are obtained and exhibited an encapsulation efficiency of over 90%. High amounts of salicylic acid are released in acidic conditions from silica nanocapsules entrapping the prodrug or the complex, leading to pH-responsive characteristics. This work demonstrates promising strategies for the encapsulation and the controlled release of hydrophilic fertilizers, pesticides or drugs.

Enhancing Environment Resistance and Bioactivity of Pesticide Enabled by Structure-Controllable Polymer Nanocarriers: Emphasizing the Role of Morphology

Nano-formulated pesticides are increasingly desired to control the insect pest and plant disease with superior efficacy for guaranteeing the high yield and quality in crop production. However, the impact of nanocarrier morphology on pesticide resistance against rainwash, photolysis, and overall pesticide bioactivity remains unknown. In this work, a series of well-defined and morphology-controllable polymer nanocarriers for pesticide are fabricated through polymerization-induced self-assembly. All these generated soft nanocarriers with hydrophobic regions exhibit excellent pesticide loading capacity over 70%. After foliar spraying, the generated one-dimensional worm-like nanopesticides exhibit an extremely high retention of 80% on leaves after 10 mm rainfall (only 10% for naked pesticide) and a good resistance to photodegradation under UV irradiation (less than 50% for worm-like micelle vs 70% for naked pesticide degradation after 20 h irradiation under 365 nm). Therefore, worm-like nanocarriers show higher bioactivity than that of spherical nanocarriers. In general, the comprehensive performance order of pesticide-loaded polymer nanocarriers is worm-like micelle > spherical vesicle > spherical micelle. Moreover, the facilely resultant soft nanocarriers of pesticides possess a remarkable low cytotoxicity and excellent biocompatibility in human cells. This nanoplatform possesses simple fabrication, structure controllability, excellent performances, and environmental friendliness, enabling the nanocarriers promising for effective pesticide delivery.

pH and Pectinase Dual-Responsive Zinc Oxide Core-Shell Nanopesticide: Efficient Control of Sclerotinia Disease and Reduction of Environmental Risks

Sclerotinia sclerotiorum is one of the fungi that cause plant diseases. It damages plants by secreting large amounts of oxalic acid and cell wall-degrading enzymes. To meet this challenge, we designed a new pH/enzyme dual-responsive nanopesticide Pro@ZnO@Pectin (PZP). This nanopesticide uses zinc oxide (ZnO) as a carrier of prochloraz (Pro) and is encapsulated with pectin. When encountering oxalic acid released by Sclerotinia sclerotiorum, the acidic environment promotes the decomposition of ZnO; at the same time, the pectinase produced by Sclerotinia sclerotiorum can also decompose the outer pectin layer of PZP, thereby promoting the effective release of the active ingredient. Experimental data showed that PZP was able to achieve an efficient release rate of 57.25% and 68.46% when pectinase was added or under acidic conditions, respectively. In addition, in vitro tests showed that the antifungal effect of PZP was comparable to that of the commercial Pro (Pro SC) on the market, and its efficacy was 1.40 times and 1.32 times that of the Pro original drug (Pro TC), respectively. Crucially, the application of PZP significantly alleviated the detrimental impacts of Pro on wheat development. Soil wetting experiments have proved that PZP primarily remained in the soil, thereby decreasing its likelihood of contaminating water sources and reducing potential risks to non-target organisms. Moreover, PZP improved the foliar wettability of Pro, lowering the contact angle to 75.06°. Residue analyses indicated that PZP did not elevate prochloraz residue levels in tomato fruits compared to conventional applications, indicating that the nanopesticide formulation does not lead to excessive pesticide buildup. In summary, the nanopesticide PZP shows great promise for effectively managing Sclerotinia sclerotiorum while minimizing environmental impact.

Optimized nanopesticide delivery of thiamethoxam to cowpeas (Vigna unguiculata) controls thrips (Megalurothrips usitatus) and reduces toxicity to non-target worker bees (Apis mellifera)

Thrips [Megalurothrips usitatus (Bagnall)] (Thysanoptera: Thripidae) is a pest that poses a serious challenge to global crop production and food supply, especially to the cowpea industry. Nano-delivery systems have broad application prospects in the prevention and control of pests in agriculture. Herein, three types of amino acid (AA) modified polysuccinimide nano-delivery carriers (PSI-GABA, PSI-ASP and PSI-GLU) were constructed with a diameter of approximately 150 nm to load thiamethoxam (THX), which enhanced THX effective distribution and use with cowpea plants. Significantly, the PSI-GLU nanocarrier effectively delivered THX to cowpea plant tissues following 6 h of soil application. Compared with commercial THX suspension (SC), the THX content in the leaves of cowpea plants was increased by 2.3 times. Confocal laser scanning microscopy revealed that the FITC-labeled PSI-GLU nanocarrier reached the leaves through the vascular system after being absorbed by the roots of cowpea plants. The PSI-GLU nanocarrier decreased the LC50 of THX from 11.45 to 7.79 mg/L and significantly enhanced the insecticidal effect. The PSI-GLU nanocarrier also improved the safety of THX to worker bees at 48 h, and moreover showed a growth-promoting effect on cowpea seedlings. These results demonstrated that the PSI-GLU nano-delivery carrier has promising uses on improving the effective utilization of THX for the sustainable control of thrips and reducing the risk to non-target pollutions.

Cocrystal engineering for sustained release of dicamba: Mitigating secondary drift and reducing leaching

The off-target effects of herbicides present significant challenges in agricultural practices, posing serious threats to both ecological systems and human health. Dicamba, one of the most widely used herbicides, is particularly problematic due to its high volatility and water solubility, which can lead to rapid environmental dispersal, non-target toxicity, and groundwater contamination. To mitigate these issues, we synthesized a novel cocrystal of dicamba and phenazine (DCB-PHE cocrystal) through a combination of theoretical prediction and mechanochemical screening. The DCB-PHE cocrystal was characterized using single-crystal and powder X-ray diffraction, Fourier-transform infrared spectroscopy (FT-IR), and thermal analysis. Compared to pure dicamba, the DCB-PHE cocrystal exhibited a substantial reduction in volatility by 59 % and a decrease in equilibrium solubility by up to 5.4 times across various temperatures (15 °C, 25 °C, 35 °C). Additionally, the dissolution rates were significantly lowered by over 94 %. Leaching experiments demonstrated that the DCB-PHE cocrystal reduced total leachate by 4.9 % and delayed percolation. In greenhouse trials, the DCB-PHE cocrystal caused less damage to exposed soy plants and enhanced herbicidal activity against target weeds, with fresh weight reduction of chicory and ryegrass by 32 % and 28 %, respectively, at the highest dosage. Furthermore, safety assays confirmed that the DCB-PHE cocrystal's safety profile was comparable to that of dicamba in terms of its impact on wheat, and it did not exhibit increased genotoxicity to broad beans. These findings suggest that the DCB-PHE cocrystal is a promising candidate for reducing the environmental impacts of dicamba while maintaining its herbicidal efficacy.

Spherical Assembly of Halloysite Clay Nanotubes as a General Reservoir of Hydrophobic Pesticides for pH-Responsive Management of Pests and Weeds

The development of smart systems for pesticidal delivery presents a significant advancement in enhancing the utilization efficiency of pesticides and mitigating environmental risks. Here an acid-responsive pesticidal delivery system using microspheres formed by the self-assembly of halloysite clay nanotubes (HNTs) is proposed. Insecticide avermectin (AVM) and herbicide prometryn (PMT) are used as two models of hydrophobic pesticide and encapsulated within the porous microspheres, followed by a coating of tannic acid/iron (TA/FeIII) complex films to generate two controlled-release pesticides, named as HCEAT and HCEPT, resulting in the loading capacity of AVM and PMT being 113.3 and 120.3 mg g-1, respectively. Both HCEAT and HCEPT exhibit responsiveness to weak acid, achieving 24 h-release ratios of 85.8% and 80.5% at a pH of 5.5. The experiment and simulation results indicate that the coordination interaction between EDTA2- and Ca2+ facilitates the spherical aggregation of HNTs. Furthermore, these novel pesticide formulations demonstrate better resistance against ultraviolet (UV) irradiation, higher foliar affinity, and less leaching effect, with negligible impact of the carrier material on plants and terrestrial organisms. This work presents a promising approach toward the development of efficient and eco-friendly pesticide formulations, greatly contributing to the sustainable advancement of agriculture.

Advancements in the nanodelivery of azole-based fungicides to control oil palm pathogenic fungi

The cultivation of oil palms is of great importance in the global agricultural industry due to its role as a primary source of vegetable oil with a wide range of applications. However, the sustainability of this industry is threatened by the presence of pathogenic fungi, particularly Ganoderma spp., which cause detrimental oil palm disease known as basal stem rot (BSR). This unfavorable condition eventually leads to significant productivity losses in the harvest, with reported yield reductions of 50-80 % in severely affected plantations. Azole-based fungicides offer potential solutions to control BSR, but their efficacy is hampered by limited solubility, penetration, distribution, and bioavailability. Recent advances in nanotechnology have paved the way for the development of nanosized delivery systems. These systems enable effective fungicide delivery to target pathogens and enhance the bioavailability of azole fungicides while minimising environmental and human health risks. In field trials, the application of azole-based nanofungicides resulted in up to 75 % reduction in disease incidence compared to conventional fungicide treatments. These innovations offer opportunities for the development of sustainable agricultural practices. This review highlights the importance of oil palm cultivation concerning the ongoing challenges posed by pathogenic fungi and examines the potential of azole-based fungicides for disease control. It also reviews recent advances in nanotechnology for fungicide delivery, explores the mechanisms behind these nanodelivery systems, and emphasises the opportunities and challenges associated with azole-based nanofungicides. Hence, this review provides valuable insights for future nanofungicide development in effective oil palm disease control.

Biocompatible Nano-Cocrystal Engineering for Targeted Herbicide Delivery: Enhancing Efficacy through Stimuli-Responsive Release and Reduced Environmental Losses

In addressing the critical challenges posed by the misuse and inefficiency of traditional pesticides, we introduce a Nano-Cocrystal material composed of the herbicide clopyralid and coformer phenazine. Developed through synergistic supramolecular self-assembly and mechanochemical nanotechnology, this Nano-Cocrystal significantly enhances pesticide performance. It exhibits a marked improvement in stability, with reductions in hygroscopicity and volatility by approximately 38%. Moreover, it intelligently modulates release according to environmental factors, such as temperature, pH, and soil inorganic salts, demonstrating decreased solubility by up to four times and improved wettability and adhesion on leaf surfaces. Importantly, the herbicidal activity surpasses that of pure clopyralid, increasing suppression rates of Medicago sativa L. and Oxalis corniculata L. by up to 27% at the highest dosage. This Nano-Cocrystal also shows enhanced crop safety and reduced genotoxicity compared to conventional formulations. Offering a blend of simplicity, cost-effectiveness, and robust stability, our findings contribute a sustainable solution to agricultural practices, favoring the safety of nontarget organisms.

Redox-Responsive Nanopesticides Based on Natural Polymers for Environmentally Safe Delivery of Pesticides with Enhanced Foliar Dispersion and Washout Resistance

Based on the modified cross-linking of the degradable natural polymers chitosan oligosaccharides (COS) and gelatin (GEL) via introduction of a functional bridge 3,3'-dithiodipropionic acid, this study constructed an environmentally responsive dinotefuran (DNF) delivery system (DNF@COS-SS-GEL). The introduction of the disulfide bond (-S-S-) endowed DNF@COS-SS-GEL with redox-responsive properties, allowing for the rapid release of pesticides when stimulated by glutathione (GSH) in the simulated insect. Compared with commercial DNF suspension concentrate (DNF-SC), DNF@COS-SS-GEL showed superior wet spreading and retention performance on cabbage leaves with a reduced contact angle (57°) at 180 s and 4-fold increased retention capacity after rainfall washout. Nanoencapsulation effectively improved the UV-photostability with only a 31.4% decomposition rate of DNF@COS-SS-GEL at 96 h. The small scale and large specific surface area resulted in excellent uptake and transportation properties in plants as well as higher bioactivity against Plutella xylostella larvae. This study will help promote sustainable agricultural development by reducing environmental pollution through improved pesticide utilization.

Current Status and Prospects of Pine Wilt Disease Management with Phytochemicals-A Review

PWD (pine wilt disease) is a devastating forest disease caused by the Bursaphelenchus xylophilus, which is the major invasive species in Asian and European countries. To control this disease, fumigation, pesticide injection, and clear cutting of epidemic trees have been widely used. But these management strategies have many limitations in terms of the effectiveness and environmental impacts, especially for the overuse of chemical pesticides. Thus, PCs (phytochemicals), the various compounds extracted from plants, have drawn extensive attention owing to their special characteristics, including abundant sources, low toxicity, high efficacy, and easy degradation. This review provides an overview of the current status of using PCs as alternative approaches to manage PWD. It discusses the efficacy of various PCs, the factors influencing their nematicidal activity, and their mechanism of action against B. xylophilus. These results will reveal the application of PCs in combating these devastating diseases and the necessity for further research.

Layer-by-layer assembled decomposable nanocapsules for light-responsive release of pesticide imidacloprid on Aphis craccivora Koch

BACKGROUND

Conventional pesticide formulations are often inefficient because of low biological uptake after spraying. Controlled release nanopesticides can release pesticides precisely in response to specific stimuli, thereby killing pests and pathogens using the least effective concentration. This study aims to develop nanocapsule-based photo-decomposable nanopesticides for efficient pesticide control.

RESULTS

The target nanopesticides were successfully fabricated using layer-by-layer assembly of the negative azobenzene-grafted hyaluronic acid (azo-HA) and positive polydimethyldiallylammonium chloride (polyDADMAC), confirmed by UV-visible, dynamic light scattering, Zeta potential and transmission electron microscopy measurements. The particle size and Zeta potential of the fabricated nanocapsules were 220 nm and +46.1 mV, respectively, and the nanocapsules were found to remain stable for up to 30 days. The optimized drug loading and encapsulation ratio of imidacloprid (IMI) in IMI/azo-HA@polyDADMAC were 21.5% and 91.3%, respectively. Cumulative release of IMI from the nanopesticides increased from ~50% to ~95% upon UV light irradiation (365 nm). The half lethal concentration (LC50) value of the nanopesticides toward Aphis craccivora Koch decreased from 2.22 to 0.55 mg L-1 upon UV light irradiation.

CONCLUSION

The trans to cis transformation of the azo group in HA decomposed IMI/azo-HA@polyDADMAC nanopesticides upon UV irradiation, thus facilitating the release of IMI, resulting in a decrease in the concentration of pesticides required for efficient pesticide control. Our work demonstrated the great potential of light-responsive nanocapsules as a controlled release nanocarrier for efficient and eco-friendly pesticide control in sustainable agriculture. © 2024 Society of Chemical Industry.

Upgrading Strategies for Managing Nematode Pests on Profitable Crops

Plant-parasitic nematodes (PPNs) reduce the high profitability of many crops and degrade their quantitative and qualitative yields globally. Traditional nematicides and other nematode control methods are being used against PPNs. However, stakeholders are searching for more sustainable and effective alternatives with limited side effects on the environment and mankind to face increased food demand, unfavorable climate change, and using unhealthy nematicides. This review focuses on upgrading the pre-procedures of PPN control as well as novel measures for their effective and durable management strategies on economically important crops. Sound and effective sampling, extraction, identification, and counting methods of PPNs and their related microorganisms, in addition to perfecting designation of nematode-host susceptibility/resistance, form the bases for these strategies. Therefore, their related frontiers should be expanded to synthesize innovative integrated solutions for these strategies. The latter involve supplanting unsafe nematicides with a new generation of safe and reliable chemical nematicidal and bionematicidal alternatives. For better efficacy, nematicidal materials and techniques should be further developed via computer-aided nematicide design. Bioinformatics devices can reinforce the potential of safe and effective biocontrol agents (BCAs) and their active components. They can delineate the interactions of bionematicides with their targeted PPN species and tackle complex diseases. Also, the functional plan of nematicides based on a blueprint of the intended goals should be further explored. Such goals can currently engage succinate dehydrogenase, acetylcholinesterase, and chitin deacetylase. Nonetheless, other biochemical compounds as novel targets for nematicides should be earnestly sought. Commonly used nematicides should be further tested for synergistic or additive function and be optimized via novel sequential, dual-purpose, and co-application of agricultural inputs, especially in integrated pest management schemes. Future directions and research priorities should address this novelty. Meanwhile, emerging bioactivated nematicides that offer reliability and nematode selectivity should be advanced for their favorable large-scale synthesis. Recent technological means should intervene to prevail over nematicide-related limitations. Nanoencapsulation can challenge production costs, effectiveness, and manufacturing defects of some nematicides. Recent progress in studying molecular plant-nematode interaction mechanisms can be further exploited for novel PPN control given related topics such as interfering RNA techniques, RNA-Seq in BCA development, and targeted genome editing. A few recent materials/techniques for control of PPNs in durable agroecosystems via decision support tools and decision support systems are addressed. The capability and effectiveness of nematicide operation harmony should be optimized via employing proper cooperative mechanisms among all partners.

Advances in the Design of Functional Cellulose Based Nanopesticide Delivery Systems

The advancement of science and technology, coupled with the growing environmental consciousness among individuals, has led to a shift in pesticide development from traditional methods characterized by inefficiency and misuse toward a more sustainable and eco-friendly approach. Cellulose, as the most abundant natural renewable resource, has opened up a new avenue in the field of biobased drug carriers by developing cellulose-based drug delivery systems. These systems offer unique advantages in terms of deposition rate enhancement, modification facilitation, and environmental impact reduction when designing nanopesticides. Consequently, their application in the field of nanoscale pesticides has gained widespread recognition. The present study provides a comprehensive review of cellulose modification methods, carrier types for cellulose-based nanopesticides delivery systems (CPDS), and various stimulus-response factors influencing pesticide release. Additionally, the main challenges in the design and application of CPDS are summarized, highlighting the immense potential of cellulose-based materials in the field of nanopesticides.

Making the Complicated Simple: A Minimizing Carrier Strategy on Innovative Nanopesticides

The flourishing progress in nanotechnology offers boundless opportunities for agriculture, particularly in the realm of nanopesticides research and development. However, concerns have been raised regarding the human and environmental safety issues stemming from the unrestrained use of non-therapeutic nanomaterials in nanopesticides. It is also important to consider whether the current development strategy of nanopesticides based on nanocarriers can strike a balance between investment and return, and if the complex material composition genuinely improves the efficiency, safety, and circularity of nanopesticides. Herein, we introduced the concept of nanopesticides with minimizing carriers (NMC) prepared through prodrug design and molecular self-assembly emerging as practical tools to address the current limitations, and compared it with nanopesticides employing non-therapeutic nanomaterials as carriers (NNC). We further summarized the current development strategy of NMC and examined potential challenges in its preparation, performance, and production. Overall, we asserted that the development of NMC systems can serve as the innovative driving force catalyzing a green and efficient revolution in nanopesticides, offering a way out of the current predicament.

Recent Advances in Stimulus-Responsive Nanocarriers for Pesticide Delivery

In an effort to make pesticide use safer, more efficient, and sustainable, micro-/nanocarriers are increasingly being utilized in agriculture to deliver pesticide-active agents, thereby reducing quantities and improving effectiveness. In the use of nanopesticides, the choice to further design and prepare pesticide stimulus-responsive nanocarriers based on changes in the plant growth environment (light, temperature, pH, enzymes, etc.) has received more and more attention from researchers. Based on this, this paper examines recent advancements in nanomaterials for the design of stimulus-responsive micro-/nanocarriers. It delves into the intricacies of preparation methods, material enhancements, in vivo/ex vivo controlled release, and application techniques for controlled release formulations. The aim is to provide a crucial reference for harnessing nanotechnology to pursue reduced pesticide use and increased efficiency.

Enzyme-responsive controlled-release materials for food preservation and crop protection - A review

The adoption of environmentally friendly and efficient methods to control food spoilage and crop diseases has become a new worldwide trend. In the medical field, various enzyme-responsive controlled-release drug formulations have been developed for precision therapy. Recently, these materials and techniques have also begun to be applied in the fields of food preservation and agricultural protection. This review of contemporary research focuses on applications of enzyme-responsive controlled-release materials in the field of food preservation and crop protection. It covers a variety of composite controlled-release materials triggered by different types of enzymes and describes in detail their composition and structure, controlled-release mechanisms, and practical application effects. The enzyme-responsive materials have been employed to control foodborne pathogens, fungi, and pests. These enzyme-responsive controlled-release materials exhibit excellent capabilities for targeted drug delivery. Upon contact with microorganisms or pests, the polymer shell of the material is degraded by secreted enzymes from these organisms, thereby releasing drugs that kill or inhibit the organisms. In addition, multi-enzyme sensitive carriers have been created to improve the effectiveness and broad spectrum of the delivery system. The increasing trend towards the use of enzyme-responsive controlled-release materials has opened up countless possibilities in food and agriculture.

Redox and Near-Infrared Light-Responsive Nanoplatform for Enhanced Pesticide Delivery and Pest Control in Rice: Construction, Efficacy, and Potential Mechanisms

The brown planthopper, Nilaparvata lugens (Stål), is a major rice pest in various Asian countries, causing significant negative impacts on rice yield and quality. In this study, we developed a novel nanoplatform (NIT@MON@CuS) for pesticide delivery that responds to redox and near-infrared light stimuli. The nanoplatform consisted of CuS nanoparticles with mesoporous organic silica (MON), loaded with nitenpyram (NIT). With an average size of 190 nm and a loading efficiency of 22%, NIT@MON@CuS exhibited remarkable thermal response in the near-infrared region, demonstrating excellent photothermal conversion ability and stability. In vitro release kinetics demonstrated the rapid release of nitenpyram under near-infrared light and glutathione conditions, facilitating a satisfactory temperature increase and accelerated drug release. The NIT@MON@CuS-treated group exhibited a higher mortality of N. lugens, increasing from 62 to 88% compared to the group treated with nitenpyram technical after 96 h. Bioassay revealed that NIT@MON@CuS significantly enhanced nitenpyram toxicity by more than 1.4-fold against both laboratory insecticide-resistant and field strains of N. lugens. Furthermore, RT-qPCR results demonstrated that MON@CuS had the capability to reduce P450 gene expression, thereby improving the sensitivity of N. lugens to insecticides. These findings suggest that MON@CuS holds great potential as an intelligent pest control platform, offering a sustainable and efficient approach to protect crops against pests.

Chitosan-thymol nanoparticle with pH responsiveness as a potential intelligent botanical fungicide against Botrytis cinerea

The practical application of essential oils (EOs) as an alternative for synthetic pesticides in agricultural production is severely limited because of their instability, high volatility, and water insolubility. Nanoencapsulation of EOs is an important strategy to overcome these limitations. In view of this, this study aimed to develop chitosan-thymol nanoparticle (NCS-Thy) with pH-responsive which can be used as an intelligent botanical fungicide to control Botrytis cinerea. The NCS-Thy nanoparticle was prepared by ionic crosslinking method with the loading capacity and encapsulation efficiency of 29.87% and 41.92%, respectively. The synthesized NCS-Thy nanoparticle was further characterized by Fourier transform infrared spectroscopy analysis, transmission electron microscopy observation, and dynamic lights scattering. The results of release kinetics and antifungal activity of NCS-Thy under different pH conditions were determined. The results showed that the NCS-Thy nanoparticle had excellent pH-responsiveness and can release more thymol under acidic conditions formed by B. cinerea, thereby achieving higher antifungal effects. Therefore, compared with unencapsulated thymol, the NCS-Thy nanoparticle had higher antifungal activity against B. cinerea in vitro. In addition, both the protective and curative efficacies of detached leaf test and pot experiment were significantly higher than those of unencapsulated thymol. Among them, the protective efficacy of NCS-Thy in the pot experiment was 78.73%, which was significantly higher than that of unencapsulated thymol with 61.13%. Therefore, the pH-responsive chitosan-thymol nano-preparation had a promising prospect of application in practical management of gray mold as an intelligent botanical fungicide.

Recent advances in stimuli-response mechanisms of nano-enabled controlled-release fertilizers and pesticides

Nanotechnology-enabled fertilizers and pesticides, especially those capable of releasing plant nutrients or pesticide active ingredients (AIs) in a controlled manner, can effectively enhance crop nutrition and protection while minimizing the environmental impacts of agricultural activities. Herein, we review the fundamentals and recent advances in nanofertilizers and nanopesticides with controlled-release properties, enabled by nanocarriers responsive to environmental and biological stimuli, including pH change, temperature, light, redox conditions, and the presence of enzymes. For pH-responsive nanocarriers, pH change can induce structural changes or degradation of the nanocarriers or cleave the bonding between nutrients/pesticide AIs and the nanocarriers. Similarly, temperature response typically involves structural changes in nanocarriers, and higher temperatures can accelerate the release by diffusion promoting or bond breaking. Photothermal materials enable responses to infrared light, and photolabile moieties (e.g., o-nitrobenzyl and azobenzene) are required for achieving ultraviolet light responses. Redox-responsive nanocarriers contain disulfide bonds or ferric iron, whereas enzyme-responsive nanocarriers typically contain the enzyme's substrate as a building block. For fabricating nanofertilizers, pH-responsive nanocarriers have been well explored, but only a few studies have reported temperature- and enzyme-responsive nanocarriers. In comparison, there have been more reports on nanopesticides, which are responsive to a range of stimuli, including many with dual- or triple-responsiveness. Nano-enabled controlled-release fertilizers and pesticides show tremendous potential for enhancing the utilization efficiency of nutrients and pesticide AIs. However, to expand their practical applications, future research should focus on optimizing their performance under realistic conditions, lowering costs, and addressing regulatory and public concerns over environmental and safety risks.

Phosphate-modified cellulose/chitosan with high drug loading for effective prevention of rice leaffolder (Cnaphalocrocis medinalis) outbreaks in fields

The continuous infestation of pests has seriously affected rice growth, yield and quality. How to reduce the use of pesticides and effectively control insect pests is a bottleneck problem. Herein, based on hydrogen bonding and electrostatic interactions, we posed a novel strategy to construct emamectin benzoate (EB) pesticide loading system using self-assembled phosphate-modified cellulose microspheres (CMP) and chitosan (CS). CMP provides more binding sites for EB loading and CS coating further enhances the carrier loading capacity up to 50.75 %, which jointly imparted pesticide photostability and pH-responsiveness. The retention capacity of EB-CMP@CS in rice growth soil reached 101.56-fold that of commercial EB, which effectively improved the absorption of pesticides during rice development. During the pest outbreak, EB-CMP@CS achieved effective pest control by increasing the pesticide content in rice stems and leaves, the control efficiency of the rice leaffolder (Cnaphalocrocis medinalis) reached 14-fold that of commercial EB, and could maintain the effective pest control effect during the booting stage of rice. Finally, EB-CMP@CS-treated paddy fields had improved yields and were free of pesticide residues in the rice grain. Therefore, EB-CMP@CS achieves effective control of rice leaffolder in paddy fields and has potential application value in green agricultural production.

Preparation and Characterization of Insecticide/Calix[4]arene Complexes and Their Enhanced Insecticidal Activities against Plutella xylostella

Applications of supramolecular materials in plant protection have attracted significant interest in recent years. To develop a feasible method to improve the efficacy and reduce the usage of chemical pesticides, the effect of calix[4]arene (C4A) inclusion on enhancing the insecticidal activity of commercial insecticides was investigated. Results showed that all three tested insecticides (chlorfenapyr, indoxacarb, and abamectin) with distinct molecular sizes and modes of action were able to form stable 1:1 host-guest complexes with C4A through simple preparation steps. The insecticidal activities of the complexes against Plutella xylostella were effectively enhanced compared to the guest molecule, with the synergism ratio being up to 3.05 (for indoxacarb). An obvious correlation was found between the enhanced insecticidal activity and the high binding affinity between insecticide and C4A, while the improvement in water solubility may not be a determining factor. The work would provide hints for the further development of functional supramolecular hosts as synergists in pesticide formulations.