Search Results (11)

Coconut cultivation faces serious challenges caused by pests and diseases, whose targets are often not reached by conventional application methods such as spraying and soil application. New control strategies, such as vegetative endotherapy, have emerged, but knowledge gaps persist regarding many aspects, especially in pesticide translocation within palm trees, which is crucial for an efficient practical field application. This study investigated the translocation of a mixture of commercial insecticides and fungicides—difenoconazole, imidacloprid, thiabendazole, cyproconazole, thiamethoxam, spirodiclofen, and carbosulfan—applied via pressurized and nonpressurized endotherapeutic methods to coconut stems. This assessment aimed to quantify the concentrations of pesticide translocation through the stem, from the application site to the plant canopy. Due to the difficulty of applying the solution to the instrument used for pressurized endotherapy, the solution had to be diluted and used at a lower volume. In experimental field conditions, stem samples were assessed at 50 and 100 cm above the application point following endotherapy treatments conducted over a period ranging from 2 to 45 days. The analyses were performed using LC-MS/MS. In the pressurized method, the highest concentrations were observed for difenoconazole (1684 µg kg⁻¹), imidacloprid (1278 µg kg⁻¹), and thiabendazole (781 µg kg⁻¹). Conversely, in the nonpressurized method, the highest concentrations were recorded for imidacloprid (5803 µg kg⁻¹), followed by difenoconazole (3660 µg kg⁻¹) and thiabendazole (2598 µg kg⁻¹). To address the issue with formulation conditions in the pressurized method and to allow a comparison between the two application methods, we simulated extrapolated results for comparison with the nonpressurized method. This evaluation aimed to evaluate both methods under similar formulation conditions (volume and concentration). The results predicted that if the solution had not been diluted, the pressurized method would present the best translocations, mainly near the plant canopy, except for carbofuran. All pesticides were translocated independently of their physical–chemical properties or formulation. No pesticide residues were detected in the coconut water and pulp up to 120 days after the endotherapy application. Full article

The extensive use of fungicides causes their continuous release into the environment through spraying, soil seepage, leaching, and runoff. It has been observed that their residues can be found in foods and a variety of environmental compartments, such as wastewater, lakes, rivers, sediments, drinking water sources (groundwater and surface water), treated water, and drinking water. A sensitive GC-MS/MS, using dynamic multiple reaction monitoring, an analytical method was developed to determine 10 fungicides (azoxystrobin, boscalid, captan, cyproconazole, cyprodinil, hexaconazole, metalaxyl, myclobutanil, paclobutrazol, and prochloraz) in drinking water. A solid-phase extraction method for sample preparations and validations was performed according to SANTE 2019 guidelines. All fungicides demonstrated mild or medium matrix effects (ME) ranging from 40.1% to 11.2%. Their recoveries ranged between 60% and 110%. The limits of detection were equal to or higher than 0.01 μg/L. The method was employed on 18 drinking water samples collected from public taps in Northern Evros, Greece, distributed in six sampling sites. Azoxystrobin, boscalid, cyproconazole, cypronidil, metalaxyl, and paclobutrazol mean concentrations did not surpass the allowable limit of 0.1 μg/L set by EU in any sampling site. Hexaconazole mean concentrations were higher than 0.1 μg/L in one sampling site, while prochloraz mean concentration showed limit exceedances in all sampling sites. Captan was not detected in any sampling site, and myclobutanil mean concentrations demonstrated exceedances of the permissible limit in four sampling sites. The presence of fungicide residues in the studied area is mainly due to the occasional point-sources pollution and preferential flow. Additionally, through the use of water, the risk of pesticides to human health was assessed for two different age groups. The sum of the hazard quotient values in each of the studied drinking water was less than unity. Consequently, the acute risk assessment procedure regards the examined drinking water as safe. Nevertheless, as prochloraz carcinogenic risk values were higher than the safe limit suggested by USEPA for both age groups, the existence of prochloraz residues raises concerns about chronic toxicity. Full article

Agents with antifungal activity play a vital role as therapeutics in health care, as do fungicides in agriculture. Effectiveness, toxicological profile, and eco-friendliness are among the properties used to select suitable substances. Furthermore, a steady supply of new agents with different modes of action is required to counter the well-known potential of human and phyto-pathogenic fungi to develop resistance against established antifungals. Here, we use an in vitro growth assay to investigate the activity of the calcineurin inhibitor tacrolimus in combination with the commercial fungicides cyproconazole and hymexazol, as well as with two earlier reported novel {2-(3-R-1H-1,2,4-triazol-5-yl)phenyl}amines, against the fungi Aspergillus niger, Colletotrichum higginsianum, Fusarium oxysporum and the oomycete Phytophthora infestans, which are notoriously harmful in agriculture. When tacrolimus was added in a concentration range from 0.25 to 25 mg/L to the tested antifungals (at a fixed concentration of 25 or 50 mg/L), the inhibitory activities were distinctly enhanced. Molecular docking calculations revealed triazole derivative 5, (2-(3-adamantan-1-yl)-1H-1,2,4-triazol-5-yl)-4-chloroaniline), as a potent inhibitor of chitin deacetylases (CDA) of Aspergillus nidulans and A. niger (AnCDA and AngCDA, respectively), which was stronger than the previously reported polyoxorin D, J075-4187, and chitotriose. The results are discussed in the context of potential synergism and molecular mode of action. Full article

Endotherapy is a potential eco-friendly alternative to conventional pesticide application techniques in coconut (Cocos nucifera Linn.) palms. Field trials applying cyproconazole by vegetative endotherapy using two different injection methods, pressurized and nonpressurized, were tested. Stem samples above the injection point were collected 2 to 45 days after application, and fruits were collected up to 45 to 120 days after application. Residue analyses on the coconut fruit and stem above the point of application of cyproconazole were performed on different days using modified QuEChERS (an acronym for “quick, easy, cheap, effective, rugged, and safe”) and LC-MS/MS MS (liquid chromatography–tandem mass spectrometry). For cyproconazole application in 2 m tall hybrid coconut palms, the residue analysis results revealed that the pressurized method achieves faster translocation and higher concentrations of cyproconazole in the upper part than the nonpressurized method, even when applying half the volume. After 120 days of application, both methods showed residue-free fruits, ensuring fruit quality. Based on these experimental results, mathematical models were developed to aid in interpreting translocation in the stem. The modeling was extrapolated for taller coconut palms, and a prediction was simulated for coconut leaf disease. The modeling was fitted to the stem translocation data, indicating that the pressurized method performs better in translocation efficiency. Full article

Biostimulators with chemical protection are a challenge in sustainable agriculture to obtain high yield, healthy, and pesticide-free wheat. The aim of this four-year spring wheat field experiment was to assess the effectivity of using herbicide, mixed fungicides protection, and a humic biostimulator. The following treatments were tested: biostimulator (S), sulfosulfuron (H), H + S, H + propiconazole + cyproconazole/spiroxamin + tebuconazole + triadimenol (H + F1 + F2), and H + F1 + F2 + S. Evaluations of wheat yield and fungal diseases (Septoria tritici blotch, eyespot, sharp eyespot, Fusarium spp.) were performed using visual and qPCR methods. Thirteen mycotoxins were analyzed by LC–MS/MS. Infestations of six weeds were examined visually. Temperatures and precipitation data of the vegetative seasons were monitored. Precipitation most affected the occurrence of leaf diseases despite the same chemical/biostimulator treatments (up to 48% Septoria tritici blotch severity for the S treatment). The highest mean yield was obtained for H + F1 + F2 + S (5.27 t ha⁻¹), while the lowest level of mycotoxins was obtained for H + F1 + F2 (221.68 µg kg⁻¹). For H + S, a greater reduction of mycotoxins was determined compared to the H treatment (27.18%), as well as a higher severity of eyespot (18%) and sharp eyespot (24%). In 2017–2020, the most effective reduction of weed infestation and Fusarium spp. DNA on ears was indicated for H + F1 + F2 (16 g and 0.88 pg g⁻¹ DNA, respectively). The greatest saved production value (196.15€) was determined for H + F1 + F2 + S. Full article

Triazole fungicides can manifest toxicity to a wide range of non-target organisms. Within this study we present a systematic review of the effects produced on the soil microbiota and activity of soil enzymes by the following triazole fungicides: cyproconazole, difenoconazole, epoxiconazole, flutriafol, hexaconazole, metconazole, myclobutanil, paclobutrazole, propiconazole, tebuconazole, tetraconazole, triadimenol, triadimefon, and triticonazole. Known effects of the triazole fungicides on the soil activity are dose dependent. High doses of triazole fungicides strongly affects the structure of the microbial communities in soil and usually decrease the soil microbial population and the activities of enzymes found in soil. Full article

Plant pathogens constantly develop resistance to antimicrobial agents, and this poses great challenges to plant protection. Therefore, there is a pressing need to search for new antimicrobials. The combined use of antimicrobial agents with different antifungal mechanisms has been recognized as a promising approach to manage plant diseases. Graphene oxide (GO) is a newly emerging and highly promising antimicrobial agent against various plant pathogens in agricultural science. In this study, the inhibitory activity of GO combined with fungicides (Mancozeb, Cyproconazol and Difenoconazole) against Fusarium graminearum was investigated in vivo and in vitro. The results revealed that the combination of GO and fungicides has significant synergistic inhibitory effects on the mycelial growth, mycelial biomass and spore germination of F. graminearum relative to single fungicides. The magnitude of synergy was found to depend on the ratio of GO and fungicide in the composite. In field tests, GO–fungicides could significantly reduce the disease incidence and disease severity, exhibiting a significantly improved control efficacy on F. graminearum. The strong synergistic activity of GO with existing fungicides demonstrates the great application potential of GO in pest management. Full article

Wheat is one of the global strategic crops and ranks third in terms of cereals production. Wheat crops are exposed to many fungal infections during their cultivation stages, some of which have the ability to secrete a number of toxic secondary metabolites that threaten the quality of the grains, consumer health, producer economics, and global trade exchange. Fifty-four random samples were collected from wheat which originated from different countries. The samples included 14 types of soft wheat to study the extent of their contamination with deoxynivalenol (DON) and T-2 toxin by auto-ELISA technology and r-biopharm microtiter plate. All samples were contaminated with DON toxin except one sample, and the values ranged between 40.7 and 1018.8 µg/kg⁻¹. The highest contamination rates were in Lithuanian wheat and the lowest was in Indian wheat. Meanwhile, the highest average level of T-2 toxin contamination was in Lithuanian wheat grains with 377.4 µg/kg⁻¹, and the lowest average was 115.3 µg/kg⁻¹ in Polish wheat. GC-MS/MS and multiple reaction monitoring mode (MRM) were used to detect 15 triazole derivatives in the collected samples, which may be used to combat fungal diseases on wheat during the growing season. Only 9 derivatives were found: simeconazole, penconazole, hexaconazole, cyproconazole, diniconazole, tebuconazole, metconazole, fenbuconazole, and difenoconazole. These derivatives varied according to the origin of the wheat samples as well as their concentration, whereas another 6 derivatives were not detected in any samples. A direct inverse relationship was found between the DON concentration in the samples and the residues of simeconazole, penconazole, diniconazole, tebuconazole, metconazole, fenbuconazole, and difenoconazole, and the T-2 toxin showed the same relationship except for tebuconazole. The safe and rational use of some triazole derivatives may be a new approach and a promising strategy to not only reduce plant diseases and their problems, but also to get rid of some mycotoxins as grain contaminants. Full article

This study’s aim was to determine the pesticide residues in 10 different vegetable commodities from the Asir region, Saudi Arabia. We evaluated 211 vegetable samples, collected from supermarkets between March 2018 and September 2018, for a total of 80 different pesticides using ultrahigh-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) and gas chromatography–tandem mass spectrometry (GC-MS/MS) after extraction with a multi-residue method (the QuEChERS method). The results were assessed according to the maximum residue limit (MRL) provided by European regulations for each pesticide in each commodity. All lettuce, cauliflower, and carrot samples were found to be free from pesticide residues. A total of 145 samples (68.7%) contained detectable pesticide residues at or lower than MRLs, and 44 samples (20.9%) contained detectable pesticide residues above MRLs. MRL values were exceeded most often in chili pepper (14 samples) and cucumber (10 samples). Methomyl, imidacloprid, metalaxyl, and cyproconazole were the most frequently detected pesticides. Based on the results of this study, we recommend that a government-supported program for the monitoring of pesticide residues in vegetables be established to promote consumers’ health and achieve sustainable farming systems. Full article

Structural isomeric pesticides are used in agriculture and may be challenging to differentiate for accurate identification in pesticide monitoring programs. Due to structural similarity, isomeric pesticides are difficult to separate chromatographically, and thus, their accurate identification may rely solely on mass spectrometric analysis (MS). In this study, we challenged the ability of high-resolution quadrupole-orbitrap (Q-Orbitrap) mass spectrometry to produce and evaluate the tandem mass spectrometry (MS/MS) product ions for the selected five pairs of isomeric pesticides from different classes: Pebulate and vernolate, methiocarb and ethiofencarb, uniconazole and cyproconazole, sebuthylazine and terbuthylazine, and orbencarb and thiobencarb. The use of Q-Orbitrap instrument with a mass error <3 ppm allowed proposed elucidation of the product ion structures with consideration of the ion formulae, data interpretation, and literature searches. Product ions unique to pebulate, vernolate, methiocarb, ethiofencarb, and uniconazole were observed. Elucidation of the observed MS/MS product ion structures was conducted, and the fragmentation pathways were proposed. This information is valuable to increase selectivity in MS/MS analysis and differentiate isomeric pesticides, and thereby reduce the rates of false positives in pesticide monitoring programs. Full article

Consumers are exposed to multiple residues of different pesticides via the diet. Therefore, EU legislation for pesticides requires the evaluation of single active substances as well as the consideration of combination effects. Hence the analysis of combined effects of substances in a broad dose range represents a key challenge to current experimental and regulatory toxicology. Here we report evidence for additive effects for (tri)azole fungicides, a widely used group of antifungal agents, in the human placental cell line Jeg-3. In addition to the triazoles cyproconazole, epoxiconazole, flusilazole and tebuconazole and the azole fungicide prochloraz also pesticides from other chemical classes assumed to act via different modes of action (i.e., the organophosphate chlorpyrifos and the triazinylsulfonylurea herbicide triflusulfuron-methyl) were investigated. Endpoints analysed include synthesis of steroid hormone production (progesterone and estradiol) and gene expression of steroidogenic and non-steroidogenic cytochrome-P-450 (CYP) enzymes. For the triazoles and prochloraz, a dose dependent inhibition of progesterone production was observed and additive effects could be confirmed for several combinations of these substances in vitro. The non-triazoles chlorpyrifos and triflusulfuron-methyl did not affect this endpoint and, in line with this finding, no additivity was observed when these substances were applied in mixtures with prochloraz. While prochloraz slightly increased aromatase expression and estradiol production and triflusulfuron-methyl decreased estradiol production, none of the other substances had effects on the expression levels of steroidogenic CYP-enzymes in Jeg-3 cells. For some triazoles, prochloraz and chlorpyrifos a significant induction of CYP1A1 mRNA expression and potential combination effects for this endpoint were observed. Inhibition of CYP1A1 mRNA induction by the AhR inhibitor CH223191 indicated AhR receptor dependence this effect. Full article