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Journal of Economic Entomology Dec 2022Wireworms are primary pests of potatoes in Canada. Presently, the highly toxic organophosphate phorate (i.e., Thimet 20G) is the only effective insecticide in use in...
Wireworms are primary pests of potatoes in Canada. Presently, the highly toxic organophosphate phorate (i.e., Thimet 20G) is the only effective insecticide in use in Canada. As such, there is an urgent need for novel alternative treatments that provide competitive tuber blemish protection and wireworm reduction with a safer human and environmental portfolio. Herein we evaluated broflanilide, a novel meta-diamide insecticide for both tuber protection and wireworm mortality. When evaluated in field trials in Agassiz, British Columbia over 6 yr, broflanilide applied as a seed piece treatment (SPT) to mother tubers at 1.5-2.0 g AI/100 kg seed (approx. 50 g AI/ha), or as an in-furrow spray (IFS) at 0.23-0.25 g AI/100 m row (approx. 25 g AI/ha) was as effective at reducing blemishes to daughter tubers by wireworms (Agriotes obscurus) as phorate (Thimet 20G at 3230 g AI/ha), bifenthrin (Capture 2EC IFS at 300 g AI/ha) and clothianidin (Titan ST at 312.5 g AI/ha). In addition, broflanilide SPT and IFS applied at the above rates reduced resident wireworms (in the field at the time of planting) by 95.4-99.0% and neonate wireworms (produced from eggs laid during the growing season) by 98.1-100%. Similar results were obtained when broflanilide IFS (nonsystemic) was paired with clothianidin SPT (systemic) for broad-spectrum potato insect pest control. Strategies for the use of broflanilide on wheat (e.g., Teraxxa F4) in rotation with potatoes (Cimegra), both registered in Canada in 2020 are discussed.
Topics: Humans; Animals; Insecticides; Solanum tuberosum; Diamide; Phorate; Coleoptera; British Columbia
PubMed: 36222544
DOI: 10.1093/jee/toac152 -
Journal of Hazardous Materials Oct 2022For the visual detection of four organophosphorus pesticides (OPs), a colorimetric aptasensor was developed based on aptamer-mediated bimetallic metal-organic frameworks...
For the visual detection of four organophosphorus pesticides (OPs), a colorimetric aptasensor was developed based on aptamer-mediated bimetallic metal-organic frameworks (MOFs) nano-polymers. Fe-Co magnetic nanoparticles (MNPs) and Fe-N-C nanozymes were prepared based on pyrolytic reaction, and were labeled with broad spectrum aptamers and complementary chains of organophosphorus pesticides respectively. The hybridization of aptamers and complementary chains led to the formation of nano-polymers. In the presence of target pesticides, they competed with complementary chains for aptamers on Fe-Co MNPs, resulting in a large number of Fe-N-C nanozymes signal labels being released into the supernatant. Fe-N-C nanozymes showed similar activity to peroxidase and catalyzed the 3,3',5,5'-tetramethylbenzidine-hydrogen peroxide (TMB-HO) color system to turn the solution blue-green under mild conditions. The magnetic probes had good selectivity and sensitivity, and were easily separated by magnetic absorption. The sensor functioned well under optimal conditions, demonstrating good stability and specificity for four pesticides: phorate, profenofos, isocarbophos and omethoate, and the detection limits of four pesticides were as low as 0.16 ng/mL, 0.16 ng/mL, 0.03 ng/mL and 1.6 ng/mL respectively, and the recovery rate of OPs residue in vegetable samples was satisfactory. The work described here provided a simple, rapid and sensitive way to construct a biosensor.
Topics: Aptamers, Nucleotide; Biosensing Techniques; Colorimetry; Hydrogen Peroxide; Limit of Detection; Metal-Organic Frameworks; Organophosphorus Compounds; Peroxidases; Pesticides; Phorate
PubMed: 35986944
DOI: 10.1016/j.jhazmat.2022.129707 -
Sensors (Basel, Switzerland) Jul 2022In this work, we reported a rapid and sensitive fluorescence assay in homogenous solution for detecting organophosphorus pesticides by using tetramethylrhodamine...
In this work, we reported a rapid and sensitive fluorescence assay in homogenous solution for detecting organophosphorus pesticides by using tetramethylrhodamine (TAMRA)-labeled aptamer and its complementary DNA (cDNA) with extended guanine (G) bases. The hybridization of cDNA and aptamer drew TAMRA close to repeated G bases, then the fluorescence of TAMRA was quenched by G bases due to the photoinduced electron transfer (PET). Upon introducing the pesticide target, the aptamer bound to pesticide instead of cDNA because of the competition between pesticide and cDNA. Thus, the TAMRA departed from G bases, resulting in fluorescence recovery of TAMRA. Under optimal conditions, the limits of detection for phorate, profenofos, isocarbophos, and omethoate were 0.333, 0.167, 0.267, and 0.333 µg/L, respectively. The method was also used in the analysis of profenofos in vegetables. Our fluorescence design was simple, rapid, and highly sensitive, which provided a means for monitoring the safety of agricultural products.
Topics: Aptamers, Nucleotide; DNA, Complementary; Fluorescence; Organophosphorus Compounds; Pesticides
PubMed: 35957269
DOI: 10.3390/s22155712 -
The Science of the Total Environment Sep 2022Organothiophosphate pesticides (OPPs) are the most commonly used pesticides, and their environmental migration brings serious water pollution and significant danger to...
Organothiophosphate pesticides (OPPs) are the most commonly used pesticides, and their environmental migration brings serious water pollution and significant danger to human health, and thus it is urgent to develop effective technologies for removal of OPPs from water. Herein, magnetic covalent organic framework (COF) with a triazine skeleton was fabricated for enhanced adsorption and removal of OPPs from water. Magnetic COF has a fluffy ball-like structure, high crystallinity, large BET surface area (1543 m g), and regular mesopores (~3.1 nm). Therefore, it displayed high adsorption rates and large adsorption capacities for four typical OPPs, pyridafenthion, phoxim, pyrimitate, and phorate. Based on adsorption kinetic and isotherms investigations, the batch experimental data of magnetic COF was effectively modeled by pseudo-second-order kinetics and the Freundlich isothermal model. The equilibrium adsorption capacities of magnetic COF composite for OPPs ranged from 163.9 to 178.6 mg g, which were about 10 times higher than the amorphous magnetic composite. The adsorption mechanism was further explored to verify the contributions of π-π, CH⋯π, and CH⋯S interactions to the adsorption of OPPs on the crystalline magnetic COF. Furthermore, the high removal rate of OPPs from the environmental water and reusability further indicated its potential in real applications as an effective adsorption material.
Topics: Adsorption; Humans; Magnetic Phenomena; Metal-Organic Frameworks; Organothiophosphates; Pesticides; Water
PubMed: 35688246
DOI: 10.1016/j.scitotenv.2022.156529 -
Toxics Apr 2022It has been estimated that approximately one in seven of all global suicides is due to pesticide self-poisoning, mostly in rural areas of developing countries....
It has been estimated that approximately one in seven of all global suicides is due to pesticide self-poisoning, mostly in rural areas of developing countries. Organophosphorus (OP) compounds are a group of pesticides exerting their toxicological effects through non-reversible inhibition of the enzyme acetylcholinesterase (AChE). Among these compounds, phorate (thimet) is one of the most dangerous compounds, the use of which is restricted in many countries. A case of intentional suicide after phorate ingestion in a 24-year-old Bengali male is described. This is the second case of suicidal ingestion of phorate reported in the forensic literature, and the first presenting complete toxicological findings.
PubMed: 35622619
DOI: 10.3390/toxics10050205 -
RSC Advances Sep 2021Understanding the interactions between nanoparticles and organophosphates is the key to developing cost-effective colorimetric pesticide detection. We have studied the...
Understanding the interactions between nanoparticles and organophosphates is the key to developing cost-effective colorimetric pesticide detection. We have studied the interaction between three different organophosphates containing the P[double bond, length as m-dash]S group and borohydride stabilized silver nanoparticles. Three different organophosphates, namely phorate, chlorpyrifos, and malathion, have been used. The colorimetric changes are corroborated with UV-visible absorption studies along with the change in particle size and zeta potential. This effect persists in the presence of NaCl solution also. The chlorpyrifos and malathion do not show significant interactions with uncapped nanoparticles over time, while phorate undergoes degradation due to the scission of the S-CH linkage. A reaction mechanism, wherein a silver and sulfur (Ag→S) complex is formed, which is in agreement with Raman spectroscopic studies is proposed. The orientations of phorate near Ag nanoparticles are discussed from the adsorption energy calculation using density functional theory.
PubMed: 35495484
DOI: 10.1039/d1ra06911j -
RSC Advances Jul 2021Surface enhanced Raman spectroscopy (SERS) is an attractive means for trace compound detection because of its high sensitivity, however, the poor reproducibility is a...
Surface enhanced Raman spectroscopy (SERS) is an attractive means for trace compound detection because of its high sensitivity, however, the poor reproducibility is a major challenge. Herein, we propose a facile SERS strategy employing the several developed test processes to improve the repeatability of the SERS analysis based on regular nylon membranes as substrates to detect trace compounds. Various methods, including reduction, immersion adsorption, and filtration, were first compared to prepare composite substrates using nylon membranes and gold nanoparticles. The substrates prepared by filtration showed the best test parallelism (RSD = 7.85%). Its limit of detection (LOD) could reach 10 g mL with a good linear relationship in the range 10 to 10 g mL. Finally, three pesticide solutions were tested to verify the substrate applicability. A superior LOD of 10 g mL was observed for thiram, whereas the LODs of both phorate and benthiocarb could reach 10 g mL. Overall, modifying nylon membrane substrates with gold nanoparticles improves the repeatability and economic viability of SERS and favors its wider commercial application for detecting trace compounds.
PubMed: 35479016
DOI: 10.1039/d1ra03490a -
Pest Management Science Jul 2022Cinmethylin, a pre-emergence herbicide inhibiting fatty acid thioesterase activity, has recently been introduced to Australian cereal cropping for the control of Lolium...
BACKGROUND
Cinmethylin, a pre-emergence herbicide inhibiting fatty acid thioesterase activity, has recently been introduced to Australian cereal cropping for the control of Lolium rigidum Gaud. (annual ryegrass). To date, there have been no confirmed cases of cinmethylin resistance identified in this species, but some populations exhibit reduced sensitivity to this herbicide. To explore the mechanism which contributes to reduced sensitivity of annual ryegrass to cinmethylin, the extent and nature of cinmethylin metabolism, using carbon-14 ( C)-labelled herbicide, were analysed in three reduced-sensitivity annual ryegrass populations, alongside a susceptible population and cinmethylin-tolerant wheat as controls.
RESULTS
All samples showed the same metabolite profile, with the extent of production of a specific water-soluble metabolite being correlated to the level of herbicide sensitivity. Application of the cytochrome P450 inhibitor phorate caused a decrease in water-soluble metabolite production as well as seedling growth in the presence of cinmethylin, indicating that reduced cinmethylin sensitivity in annual ryegrass could be wholly or partially due to oxidative modification of cinmethylin.
CONCLUSION
Because annual ryegrass has the potential to metabolize cinmethylin in the same way as wheat, careful stewardship is required to ensure the longevity of this herbicide. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Topics: Australia; Carbon Radioisotopes; Herbicide Resistance; Herbicides; Lolium; Triticum; Water
PubMed: 35470951
DOI: 10.1002/ps.6947 -
Toxics Apr 2022Transmission Electron Microscopic (TEM) assessments were performed on the renal cells of common carp to observe the deleterious effects of two organophosphate...
Transmission Electron Microscopic (TEM) assessments were performed on the renal cells of common carp to observe the deleterious effects of two organophosphate insecticides, Phorate and Dimethoate. Pesticides such as Phorate and Dimethoate often pollute aquatic systems where they may negatively impact fish, but so far, the ultrastructural toxicity of these pesticides remains poorly understood. Here, we use Transmission Electron Microscopy (TEM) to determine how acute exposure to sublethal concentrations of these two pesticides may affect the renal cells of common carp . For each insecticide, the fish were divided in four experimental conditions: a control and three different exposure concentrations of the pesticide. The Phorate treated fish were exposed to three sublethal concentrations of 0.2 mg/L, 0.4 mg/L, 0.6 mg/L for a duration of 24, 48 & 72 h. The dimethoate treated fish were exposed to three sublethal concentrations of 0.005 mL/L, 0.01 mL/L, 0.015 mL/L for a duration of 24, 48 and 72 h. The two-dimensional transmission electron microscopy revealed ultrastructural abnormalities in the treated fish renal cells when exposed to two toxicants including deformation in the glomerulus, vacuolization of cytoplasm, degenerative nucleus and damaged mitochondria. Furthermore, the ultrastructural abnormalities were more prominent with the increase in the concentrations of both the insecticides and also with their exposure period. Overall, these results provide important baseline data on the ultrastructural toxicity of Phorate and Dimethoate and will allow important follow-up studies to further elucidate the underlying cellular mechanisms of pesticide toxicity in wildlife.
PubMed: 35448438
DOI: 10.3390/toxics10040177 -
Zhongguo Zhong Yao Za Zhi = Zhongguo... Mar 2022The demand for Angelicae Sinensis Radix, the dry root of Angelica sinensis, has been increasing year by year. However, the continuous cropping obstacles, frequent...
The demand for Angelicae Sinensis Radix, the dry root of Angelica sinensis, has been increasing year by year. However, the continuous cropping obstacles, frequent occurrence of pests and diseases, overuse of chemical pesticides, excessive pesticide residues and other problems in Angelicae Sinensis Radix production have attracted much attention. In this paper, we summarized the common diseases and pests attacking Angelica sinensis as well as the detection methods and characteristics of pesticide residues in Angelicae Sinensis Radix from 2002 to 2021. Additionally, we compared the limit standards of pesticide residues in Angelicae Sinensis Radix in and out of China and put forward suggestions for the high-quality and green development of Angelicae Sinensis Radix industry conside-ring the existing problems. The pesticide residues in Angelicae Sinensis Radix have been changing from organochlorines to organophosphorus pesticides. In recent years, some organophosphorus pesticides such as phorate, phoxim, isofenphos-methyl, phorate-sulfoxide, fenamiphos, isocarbophos, omethoate, and triazophos in Angelicae Sinensis Radix have seriously exceeded the standards. The detection methods of pesticide residues has evolved from chromatography to high performance chromatography-mass spectrometry, gas chromatography-mass spectrometry(GC-MS), and liquid chromatography-mass spectrometry(LC-MS), and some new detection techniques such as immunoassay have also been applied. Pesticide residues have become a primary factor that restricting the development of Angelicae Sinensis Radix industry. Therefore, moderate application of pesticides, establishment of ecological planting system, and strict limit standards of pesticide residues are necessary to solve the pesticide residue problem.
Topics: Angelica sinensis; Chromatography, Liquid; Organophosphorus Compounds; Pesticide Residues; Pesticides
PubMed: 35347942
DOI: 10.19540/j.cnki.cjcmm.20211220.102