Pesticide Residues in Vegetables and Fruits from Farmer Markets and Associated Dietary Risks.

The use of pesticides leads to an increase in agricultural production but also causes harmful effects on human health when excessively used. For safe consumption, pesticide residues should be below the maximum residual limits (MRLs). In this study, the residual levels of pesticides in vegetables and fruits collected from farmers' markets in Sharkia Governorate, Egypt were investigated using LC-MS/MS and GC-MS/MS. A total number of 40 pesticides were detected in the tested vegetable and fruit samples. Insecticides were the highest group in detection frequency with 85% and 69% appearance in vegetables and fruits, respectively. Cucumber and apple samples were found to have the highest number of pesticide residues. The mean residue levels ranged from 7 to 951 µg kg-1 (in vegetable samples) and from 8 to 775 µg kg-1 (in fruit samples). It was found that 35 (40.7%) out of 86 pesticide residues detected in vegetables and 35 (38.9%) out of 90 pesticide residues detected in fruits exceeded MRLs. Results for lambda-cyhalothrin, fipronil, dimothoate, and omethoate in spinach, zucchini, kaki, and strawberry, respectively, can cause acute or chronic risks when consumed at 0.1 and 0.2 kg day-1. Therefore, it is necessary for food safety and security to continuously monitor pesticide residues in fruits and vegetables in markets.

Biological silicon nanoparticles maximize the efficiency of nematicides against biotic stress induced by Meloidogyne incognita in eggplant.

Nemours effective management tactics were used to reduce world crop losses caused by plant-parasitic nematodes. Nowadays the metallic nanoparticles are easily developed with desired size and shape. Nanoparticles (NPs) technology becomes a recognized need for researchers. Ecofriendly and biosafe SiNPs are developed from microorganisms. Recently, silicon nanoparticles (SiNPs) have gained novel pesticide properties against numerous agricultural pests. This study assessed the biosynthesis of SiNPs from Fusarium oxysporum SM5. The obtained SiNPs were spherical with a size of 45 nm and a negative charge of -25.65. The nematocidal effect of SiNPs against egg hatching and second-stage juveniles (J2) of root-knot nematode (RKN) (Meloidogyne incognita) was evaluated on eggplant,Solanum melongena L. plants. In vitro, all tested SiNPs concentrations significantly (p ≤ 0.05) inhibited the percentage of egg hatching at a different time of exposure than control. Meanwhile, after 72 h, the percent mortality of J2 ranged from 87.00 % to 98.50 %, with SiNPs (100 and 200 ppm). The combination between SiNPs and the half-recommended doses (0.5 RD) of commercial nematicides namely,  fenamiphos (Femax 40 % EC)R, nemathorin (Fosthiazate 10 % WG) R, and fosthiazate (krenkel 75 % EC) R confirmed the increase of egg hatching inhibition and J2 mortality after exposure to SiNPs (100 ppm) mixed with 0.5 RD of synthetic nematicides. The findings suggest that the combination between SiNPs, and 0.5 RD of nematicides reduced nematode reproduction, gall formation, egg masses on roots and final population of J2 in the soil. Therefore, improving the plant growth parameters by reducing the M. incognita population.

Do the herbicides pinoxaden, tribenuron-methyl, and pyroxsulam influence wheat (Triticum aestivum L.) physiological parameters?

Herbicides reduce the unsafe effects of weeds, but they are likely to have negative impact on essential and secondary metabolism in crops. However, the combined effect of different herbicides on chemical constituents of different varieties of wheat is still not fully obvious. The current investigation was carried out to determine the effects of three post-emergence herbicides (pinoxaden, tribenuron-methyl, and pyroxsulam) on total protein, lipid, and carbohydrate concentrations of three bread wheat cultivars (Misr 1, Giza 171, and Gemmiza 11). These herbicides were added individually and in combinations at recommended and/or half recommended doses. Our findings revealed that the individual application of herbicides decreased total protein and total lipid concentrations in fresh shoots of the three studied wheat cultivars, but increased total carbohydrate concentration. Combined addition of herbicides at recommended and half recommended doses generally decreased the concentrations of total proteins, total lipids, and total carbohydrates. However, the combined addition of tribenuron-methyl and pinoxaden at recommended dose enhanced total protein and total lipid concentrations under Misr1 and Gemmiza 11 cultivars compared to control treatment. Furthermore, the combined addition of tribenuron-methyl and pyroxsulam at half recommended dose enhanced total protein concentration in Giza 171 up to 15.05% and Gemmiza 11 up to 15.09% cultivars, and total lipid concentration in Misr 1 (7.53%) and Giza 171 (9.81%) cultivars against control treatment, where it was the lowest. Total carbohydrate concentration was enhanced by the sole application of pinoxaden by 53.55%, 52.40%, and 51.79% for Misr 1, Giza 171, and Gemmiza 11 cultivars, respectively. Moreover, individual or combined additions of the studied pesticides at recommended and half recommended doses negatively affected wheat grains under all cultivars via decreasing their concentration of nutrients (nitrogen, phosphorus, and potassium) as well as total protein and total carbohydrates. The highest reduction of nitrogen, phosphorus, and potassium concentrations compared to control was observed when tribenuron-methyl+pyroxsulam was applied at the half recommended dose under the three studied cultivars. However, the combined application of tribenuron-methyl+pyroxsulam at the half recommended dose caused the great depression in total proteins and total carbohydrates of wheat grains. Under the stress effect of herbicides, individual application of pinoxaden gave the best results for nitrogen and potassium content as well as total protein and total carbohydrate concentrations in the three studied wheat grain cultivars.

Electrophoretic banding patterns of protein induced by pinoxaden, tribenuron-methyl, and pyroxsulam herbicides in wheat leaves (Triticum aestivum L.).

Herbicides are the most effective tool against weed flora in cereal crops that help to maintain and increase crop yields. This investigation was conducted in the winter season of 2018 to study the stress effect of three post-emergence herbicides including pinoxaden, tribenuron-methyl, and pyroxsulam on the biochemical changes at the molecular cell level of wheat. These herbicides were applied either lonely with a rate of 0.45 L.ha-1, 22.5 gm.ha-1, and 0.16 Ib a.i/A, respectively, or in combinations together on three Egyptian varieties of bread wheat known as Misr 1, Giza17 1, and Gemmiza 11. Firstly, the abovementioned herbicides were used at the recommended and half recommended doses with their combinations for these varieties to investigate DNA-protein linkage as a signal effect of herbicides at the molecular cell level.Our data showed that the treatment of wheat varieties with the tested herbicides induced new bands with low and high molecular weights of 37.49, 40.08, 146.55, and 147.23 KDa with relative mobility of 0.1574, 0.1603, 0.2166, and 0.2168, respectively. These bands were not presented in the control treatment, suggesting that it might be used as a biochemical marker for plant defense genes. Meanwhile, the control treatment exhibited only five or six bands in the three varieties. However, the tested varieties showed that the same number of bands, the molecular weights of bands, and their relative mobility were significantly varied between the single and the combinations treatment of herbicides. The best treatment was achieved by the combination between pinoxaden and tribenuron-methyl at a recommended dose which induced a large number of protein bands compared to the control treatment on the wheat variety cv. Misr 1, which gave one band with low molecular weight 71.44 KDa at Rf 0.1854 and other with the highest molecular weight 147.23 KDa at Rf 0.2168, compared to the control treatment.

Fluctuation in amino acids content in Triticum aestivum L. cultivars as an indicator on the impact of post-emergence herbicides in controlling weeds.

This study was carried out in a demonstrated field in El-Sharkia Governorate, Egypt, during the winter of season 2020 to evaluate the leverage of four post-emergence herbicides i.e., tribenuron-methyl, clodinafop- propargyl, pyroxsulam and pinoxaden compared to control on total protein and amino acid contents in three wheat cultivars (Shandwel 1, Giza 171, and Sakha 95). Generally, the use of foliar herbicides led to a significant decrease in essential, non-essential amino acids and protein contents. However, tribenuran-methyl herbicide signifcantly increased the levels of proline, glycine, arginine, and histidine, but cystine and threonine not affected as compared to control. On the other hand, foliar herbicide application was significantly increased physiological , biochemical parameters and yield of Shandweel cultivar as compared to the other varieties. The physiological and biochemical models of dual-herbicide-tolerant wheat cultivars add to our understanding of the crop. In recent agricultural systems, herbicide tolerant plants are important for long-term weed management. Therefore, the study recommended the safely usage of Tribenuran-methyl as foliar herbicide in weed managment.