Dissipation behaviors of deltamethrin, emamectin benzoate and hexythiazox in grape under field conditions

The objective of this study was to evaluate the dissipation kinetics of deltamethrin, emamectin benzoate, and hexythiazox in grapes. The QuEChERS method was employed and validated for the precise determination of these three pesticides using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Excellent linearity was observed with regression coefficients exceeding 0.998. Notably, the limits of quantification (LOQ) were significantly lower than the maximum residue limits (MRLs) established for grapes by the European Union. The QuEChERS method l recovered 93.23% of the pesticides with an acceptable RSD of 5.35% (n = 180), demonstrating its suitability for quantifying them in grapes. Half-lives of deltamethrin, emamectin benzoate, and hexythiazox in grapes were 2.62-2.68 days, 8.15-7.30 days, and 3.24-4.01 days, respectively, for both single and double doses. Residues of all pesticides fell below the MRLs by the preharvest interval. This suggests that their application can be considered safe for grapes, ensuring both pest control and consumer safety.

Dissipation kinetics of some pesticides applied singly or in mixtures in/on grape leaf

BACKGROUND

Grape and leaf quality are often severely reduced by fungi such as grey rot Botrytis cinerea Pers., powdery mildew Erysiphe necator Schwein, and downy mildew Plasmopara viticola (Berk. & M.A.Curtis) Berl. & De Toni and by insects such as Otiorhynchus spp., European grapevine moth Lobesia botrana Den.-Schiff., vine mealybug Planococcus citri Risso, and grape erineum mite Colomerus vitis Pgst. Various pesticides are often applied to mitigate these pest problems. These chemicals used singly as well as in the form of a mixture can leave residues on or in the crop. It is therefore of great importance to study the dissipation of the pesticides applied alone and in mixtures to this crop to protect consumers.

RESULTS

The dissipation kinetics of cypermethrin, boscalid, deltamethrin, kresoxim-methyl, lambda-cyhalothrin, metalaxyl-M, metrafenone, and triadimenol residues were studied in vine leaves grown under sunny conditions in Turkey. The dissipation rate for singly applied pesticides followed first-order kinetics, with half-lifes in grape leaves in the range of 1.85-7.22 days. Changes in the degradation process of pesticide residues were determined after application, as both single applications and mixtures. The degradation of boscalid, cymoxanil, deltamethrin and metalaxyl-M accelerated while the degradation of cypermethrin, kresoxim-methyl, and lambda-cyhalothrin slowed down in mixtures of pesticides.

CONCLUSION

The use of pesticides in mixtures leads to slower degradation and higher residues for some active ingredients and faster degradation and fewer residues for other active ingredients. Therefore, pesticide mixtures should not be applied in the field without having detailed information about their ingredients. © 2022 Society of Chemical Industry.

Efficacy of some washing solutions for removal of pesticide residues in lettuce

Background

When previous studies were examined, it was reported that a wide variety of pesticide residues were detected in lettuce (Bakırcı et al. in Food Chem 160:379–392, 2014; Balkan and Yılmaz in Food Chem 384:132516, 2022; Qin et al. in Food Res Int 72:161–167, 2015; Selim et al. in Res J Environ Sci 5:248–258, 2011). In addition, pesticide-contaminated lettuce poses a risk to consumers as it is a fresh food that is eaten raw. Therefore, pesticide removal processes must be applied before consumption. Some pesticide removal process, such as storage and heat treatment cannot be applied to lettuce because of unshelled, no long shelf life and consuming as fresh. Different practical methods are needed for the removal of pesticides process. The recommendations of suitable methods for cleaning salad materials in ready-to-eat sector, hotels, restaurants and homes are very important. It is important to reduce pesticide residues in vegetables and fruits that are consumed raw by washing them with non-toxic solutions. These approaches aim to protect public health. The study conducted in 2021 determined the effect of various washing treatments. For this purpose, before the washing trials, QuEChERS method was validated for determination of 7 pesticides in lettuce, by liquid chromatography–tandem mass spectrometry (LC–MS/MS). Lettuce plants were grown in the greenhouse for the study. Lettuces were brought to the laboratory 24 h after pesticides were applied in the greenhouse. The samples were kept in 2 L washing solution for pesticide analysis.

Results

The processing factor values of all washing applications were found below 1. This result shows that the residue level was reduced by washing solutions. Among the washing solution treatments, the rice vinegar washing solution was found to be most effective in reducing the pesticide residues which was due to the high degree in the pesticide degradation. Washing with filtered rice water also exhibited equivalent reduction capability similar to rice vinegar.

Conclusions

The effectiveness of washing solutions was different for boscalid, deltamethrin, fluopcolide, fluopyram, pyrimethanil, pyraclostrobin and sulfoxaflor. However, when the average removal of these pesticides was evaluated, the most effective solutions were rice vinegar, filtered rice water, carbonated water, NaCl + grape vinegar, hot tap water (40 °C), grape vinegar (6% acetic acid), grape vinegar + water, cold tap water (20 °C), lemon juice, baking soda water, grape vinegar (8% acetic acid), filtered mint water and grape vinegar (4% acetic acid), respectively. It was concluded that some of the solutions used in this study can significantly reduce exposure to pesticides for consumers.

Castleman's disease masquerading as sigmoid colon tumor and Hodgkin lymphoma

Castleman's disease is a benign lymphoid neoplasm first reported as hyperplasia of mediastinal lymph nodes. Some authors referred to the lesions as isolated tumors, described as a variant of Hodgkin's disease with a possibility of a malignant potential and others proposed that the lymphoid masses were of a hamartomatous nature. Three histologic variants and two clinical types of the disease have been described. The disease may occur in almost any area in which lymph nodes are normally found. The most common locations are thorax (63%), abdomen (11%) and axilla (4%). We report two separate histologic types of Castleman's disease which were rare in the literature, mimicking sigmoid colon tumor and Hodgkin lymphoma. The diagnostic and therapeutic aspects of this rare entity is discussed.