Understanding the lethal effects of pesticides nano formulations on the targeted organisms (pathogens) and the non-targeted organisms (fish, earthworms, etc) is essential in assessing the probable ...impact of new technologies on agriculture and environment. Here we evaluated the bioactivity and the biotoxicity of new type of fungicide smart-delivery formulation based on conjugating carboxymethylated-β-glucans on the mesoporous silica nanoparticles (MSNs) surface after loading chlorothalonil (CHT) fungicide in the MSNs pores. The obtained formulation has been characterized with FE-SEM, and HR-TEM. The CHT loading efficiency has been measured with TGA. The bioactivity of the obtained formulation (CHT@MSNs-β-glucans) has been tested against four pathogens, fusarium head blight (Fusarium graminearum), sheath rot (Sarocladium oryzae), rice sheath blight (Rhizoctonia solani), and soyabean anthracnose (Colletotrichum truncatum) compared with CHT WP 75% commercial formulation (CHT-WP) and technical CHT. The environmental biotoxicity of CHT@MSNs-β-glucans compared with CHT-WP has been tested toward earthworm (Eisenia fetida) and zebra fish (Danio rerio). The results showed that CHT@MSNs-β-glucans has an excellent bioactivity against the subjected pathogens with better inhabiting effects than CHT-WP. CHT@MSNs-β-glucans toxicity to Eisenia fetida was found 2.25 times lower than CHT-WP toxicity. The LC50 of CHT@MSNs-β-glucans to zebra fish after the first 24h was 2.93 times higher than CHT-WP. After 96h of treatment, the LC50 of CHT@MSNs-β-glucans was 2.66 times higher than CHT-WP. This work highlighted the necessity to increase the mandatory bioassays of nano formulations with the major non-target organisms in the environmental risk assessment of new pesticide formulations.
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•In vitro bioassays used to assess toxicity of CHT-WP vs. CHT@MSNs-β-glucans.•CHT@MSNs-β-glucans bioactivity against pathogens is better than CHT-WP.•CHT@MSNs-β-glucans has lower toxicity to Eisenia fetida than CHT-WP.•CHT@MSNs-β-glucans has lower toxicity to zebra fish.•CHT@MSNs-β-glucans possessed good biocompatibility and biosafety.
In this study, pH-responsive LC@O-CMCS/PU nanoparticles were prepared by encapsulating λ-cyhalothrin (LC) with O-carboxymethyl chitosan (O-CMCS) to form LC/O-CMCS and then covering it with ...polyurethane (PU). Characterization and performance test results demonstrate that LC@O-CMCS/PU had good alkaline release properties and pesticide loading performance. Compared to commercial formulations containing large amounts of emulsifiers (e.g., emulsifiable concentrate, EC), LC@O-CMCS/PU showed better leaf-surface adhesion. On the dried pesticide-applied surfaces, the acute contact toxicity of LC@O-CMCS/PU to Harmonia axyridis (H. axyridis) was nearly 20 times lower than that of LC EC. Due to the slow-releasing property of LC@O-CMCS/PU, only 16.38 % of LC was released at 48 h in dew and effectively reduced the toxicity of dew. On the pesticide-applied leaves with dew, exposure to the LC (EC) caused 86.66 % mortality of H. axyridis larvae significantly higher than the LC@O-CMCS/PU, which was only 16.66 % lethality. Additionally, quantitative analysis demonstrated 11.33 mg/kg of λ-cyhalothrin in the dew on LC@O-CMCS/PU lower than LC (EC) with 4.54 mg/kg. In summary, LC@O-CMCS/PU effectively improves the safety of λ-cyhalothrin to H. axyridis and has great potential to be used in pest control combining natural enemies and chemical pesticides.
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In order to control the
Solenopsis invicta
(
S. invicta
) in a safe and ecofriendly manner, this study evaluated the fumigating activity of garlic and its effect on the behavior of
S. invicta
. The ...volatile compounds and chemical constituents from garlic were collected by solid phase micro-extraction and identified by gas chromatography–mass spectrometry (GC–MS). The results showed that garlic contains 21 compounds, and that diallyl disulfide (46.51%) and (E)—1—Allyl—2—(prop—1—en—1—yl) disulfane (34.68%) were the main constituents in garlic. In addition, garlic showed strong fumigant activity and behavioral inhibition against workers. The LC
50
values of diallyl disulfide and methyl allyl disulfide against
S. invicta
at 12 h were 0.05 and 0.07 μg/L, respectively. The grasping and walking abilities of ants were significantly suppressed. Moreover, minor workers were more susceptible than major workers. Thus,
S. invicta
can be controlled with garlic and some of its compounds as an eco-friendly approach. Results from the study could provide valuable advances for future fumigant development and possible utility in fumigant use.
Damage to the growing ears by Spodoptera frugiperda is a major economic burden, therefore, the development of a novel targeted treatment with safe, environmentally friendly, and effective is ...necessary to control the damage of S. frugiperda in maize ears. In this study, chitosan/sodium alginate hydrogel rings loaded with chlorantraniliprole (CLAP) were prepared by physical embedding and ionic cross-linking method. The CLAP-loaded hydrogel rings were evaluated for their morphology, loading efficiency, encapsulation efficiency, and release kinetics at different pH levels. The efficacy of the CLAP-loaded hydrogel rings and CLAP suspension were evaluated under field conditions for control of S. frugiperda in maize ears, and the distribution and dissipation of CLAP on maize ears were investigated. The results of the two-year trial showed that the insecticidal effects of the CLAP-loaded hydrogel rings treatment were significantly improved contrasted with the use of CLAP suspension, and increased the transfer efficiency of the pesticide from maize bracts to maize kernels. The terminal residues showed that it is safe to use CLAP suspension and CLAP-loaded hydrogel rings on maize ears. This study provides guidance for the use of pesticides to control pests in maize ears in rainfall-rich areas.
Fabricated chlorantraniliprole loaded chitosan/alginate hydrogel rings effectively control Spodoptera frugiperda in maizes ears. Display omitted
•An environmentally friendly slow-release system was developed for the control of Spodoptera frugiperda on maize ears.•The application of chlorantraniliprole-loaded hydrogel rings resulted in a longer persistence of the pesticide.•The hydrogel rings improved the transfer efficiency of pesticide transfer from maize bracts to maize kernels.•The hydrogel rings reduce the drift of pesticides during the spraying process and reduce the impact on the environment.
Understanding the impact of chitosan-based nanoparticles (NPs) on ecological systems is vital for assessing their environmental behavior and safety. In this study, we investigated the effects of ...pyraclostrobin@chitosan-based nanoparticles (NPs.PYR) on microbial communities in a pond. NPs.PYR significantly impacted the abundance of microbial communities in the pond, compared with the commercial pesticide suspensions. We employed Chlorella sp. as a representative microorganism to explain this phenomenon and found that the NPs and NPs.PYR treatments induced a rapid decrease in the abundance of Chlorella sp. This phenomenon can be attributed to the electrostatic interaction between the NPs and microorganisms, along with the affinity of the microorganisms’ extracellular polymers to the chitosan-based NPs, resulting in the cosettlement of the microorganisms with these NPs. The NPs.PYR migrated from the overlying water to the sediment, decreasing the PYR concentration in the overlying water. The mortality of zebrafish specimens exposed to NPs.PYR was significantly lower than that of the specimens exposed to pyraclostrobin suspension concentrate. These results suggest that the prepared chitosan-based nanopesticide tends to aggregate with microorganisms, leading to cosettlement and reduced pesticide levels in the overlying water, thus enhancing the safety of nontarget animals.
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•Chitosan-based nanopesticide significantly impact the abundance of overlying water microbial communities.•Chitosan-based nanopesticide can aggregate and precipitate alongside microalgae such as Chlorella sp.•Chitosan-based nanopesticide can mitigate eutrophication levels of overlying water.•Compared commercial pesticide suspensions, chitosan-based nanopesticide exhibit higher safety for zebrafish.
A chitosan-based nanoparticle was prepared using chitosan (CS) and O-carboxymethyl chitosan (O-CMCS). Our study revealed that chitosan/O-carboxymethyl chitosan/tebuconazole nanoparticles ...(CS/O-CMCS/TBA NPs) exhibited superior antifungal activity, foliar adhesion, and microbial target adhesion performance compared to commercial suspension concentrate (SC). The antifungal activity of CS/O-CMCS/TBA NPs against C. gloeosporioides, with a 3.13-fold increase in efficacy over TBA (SC). We also found that low concentrations of CS/O-CMCS NPs promoted the growth of C. gloeosporioides and enhanced the fungal catabolism of chitosan. Overall, the CS/O-CMCS/TBA NPs were found to possess the remarkable capability to selectively aggregate around pathogenic microorganisms and CS/O-CMCS NPs can enhance the fungal catabolism of chitosan. CS/O-CMCS/TBA NPs, as a “sugar-coated bomb”, was a promising asset for effective plant disease management and pesticide utilization through the affinity of chitosan-based nanoparticles and C. gloeosporioides, enabling targeted delivery and targeted release of their encapsulated active ingredient, which was important for the development and application of biocompatible chitosan-based nanopesticides.
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Rotenone is a botanical pesticide and has long been used for control of insect pests and also as a natural piscicide for management of fish populations in many countries. Field application for pest ...control, however, often encounters the movement of rotenone into surface water due to spray drift or surface runoff after rainfall, which could potentially result in water pollution and unexpected death of fishes. To minimize its effect on freshwater and the problem of fish dying, one solution was to encapsulate rotenone in specific microspheres, limiting its release and reducing its toxicity since rotenone can be quickly degraded under sunlight. In this study, pH-responsive alginate-based microspheres were synthesized to encapsulating rotenone, which were designated as rotenone beads. The rotenone beads, along with alginate beads (devoid of rotenone) were characterized and evaluated for their responses to pH and effects on zebrafish. Results showed that the microspheres had high loading efficiency (4.41%, w/w) for rotenone, and rotenone beads well responded to solution pH levels. The cumulative release rates of rotenone from the beads were 27.91%, 42.72%, and 90.24% at pH 5.5, 7.0, and 9.0, respectively. Under acidic conditions, the rotenone release rate was lower due to hydrogen bonding. On the contrary, rotenone became more quickly released at the high pH due to intermolecular repulsion. The toxicity of rotenone beads to zebrafish and fish embryos at a pH of 5.5 was reduced by 2- and 4-fold than chemical rotenone. Since pH levels in most freshwater lakes, ponds, and streams vary from 6 to 8, rotenone release from the beads in such freshwater could be limited. Thus, the synthesized rotenone beads could be relatively safely used for pest control with limited effects on freshwater fishers.
•Botanical pesticide rotenone was encapsulated in alginate-based microspheres.•Rotenone beads were pH sensitive and released rotenone in a controlled fashion.•Rotenone beads were less toxic zebrafish and fish embryos than chemical rotenone.•Rotenone beads could be safely used for pest control with little effects on fish.
Spodoptera frugiperda
(J.E. Smith) is an invasive pest, causing significant corn yield losses. Currently, its control is largely dependent on foliar spray with insecticides. Application of ...insecticides on the cuticular wax and linear long leaves of corn, however, is sometimes ineffective because sprayed droplets may bounce off the leaves and also
S. frugiperda
larvaes are deeply embedded in the corn whorl and usually emerge at night. Improving insecticide adhesion on corn leaves could increase control efficacy. In this study, three 20% chlorantraniliprole emulsifiable concentrates (CECs) were formulated using neem, sunflower, and grape seed oils. The wettability, emulsion stability, physicochemical properties, control efficiency, and absorption levels of CECs were evaluated by comparison with a 200 g L
−1
chlorantraniliprole suspension concentrate (SC). Results indicated that CECs had appropriate emulsification and wetting properties. The work of adhesion of SC was over 1.4-fold higher than CECs, and the surface tension and contact angle of CECs were 1.87–1.94 and 1.69–2.05-fold lower than SC, respectively, which was effective in reducing chlorantraniliprole drift and improving the deposition. CECs and SC were used for controlling
S. frugiperda
larvae in corn plants in Guangzhou and Nanning, respectively. Results showed that CECs were 1.45–1.60-fold more effective than SC in reducing
S. frugiperda
larvae in 14 days. The enhanced control efficacy of CECs was related to its improved adhesion performance on corn leaves as chlorantraniliprole on corn leaves were significantly higher, and half-lives of CECs were longer than SC. Our study suggests that improving adhesion performance of a popular insecticide can significantly improve control efficacy of
S. frugiperda
larvae in corn plants.
Interactive release formulations are one of the best strategies for enhancing pesticides usage. A 112 nm α-amylase enzyme-responsive nanosystem loaded with abamectin (ABM) was synthesized by ...attaching carboxymethyl starch (CMS) to the surface of hollow mesoporous silica (HMS) to improve ABM insecticidal activity and photostability. ABM-loaded HMS–CMS characteristics were tested. ABM release behavior under different pH levels and in the presence or absence of α-amylase enzyme was investigated. The ultraviolet (UV) protection ability and the insecticidal activity against one of the model insects, Spodoptera littoralis, were examined. The adhesion properties of ABM-loaded HMS–CMS on corn leaves have been tested. The prepared ABM-loaded HMS–CMS presented a high loading efficacy of up to 24.77% and enzymatic release dependency of up to 88.34% after 17 days of adding α-amylase enzyme. After 60 h of UV radiation, only 17.7% of the loaded ABM into HMS–CMS has deteriorated. ABM-loaded HMS–CMS showed better insecticidal activity against S. littoralis than abamectin commercial formulation (ABM-EC). After 14 days, the LC50 of ABM-loaded HMS–CMS was 51.7% lower than that of ABM-EC. The prepared ABM-loaded HMS–CMS showed excellent adhesion on corn leaves. We recommend using such formulations to achieve better and sustainable farming.
