Degradation profile and safety evaluation of methomyl residues in tomato and soil

Malhat, Farag; Watanabe, Hirozumi; Youssef, Ahmed M.

doi:10.1515/hppj-2015-0008

Cited by 17 publications

(8 citation statements)

References 31 publications

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“…In the present study, the residue concentrations of methomyl, at 2.6 mg kg -1 , were below the MRL 1 day after treatment (Table 2); at 5.1 days, its half-life is in agreement with results obtained by Reeve et al (1992), which showed that variable half-lives of methomyl in grape foliage in 36 U.S. fi elds ranged from 1 to 7.7 days. In contrast, the half-life of methomyl in qat leaves, as demonstrated in our study, is longer than the reported half-lives in other studies of other plants e.g., 0.9-1.34 days for tomatoes (Gambacorta et al, 2005;Malhat et al, 2015) and 0.88-0.94 days for okra fruits (Aktar et al, 2008). The half-life of methomyl in plants increases signifi cantly with the progression of the summer months (Reeve et al, 1992) due to the slow growth of plants and, consequently, less effi ciency in the degradation of the pesticides.…”

Section: Resultscontrasting

confidence: 81%

Persistence of imidacloprid, acetamiprid and methomyl in qat leaves

Al-Rajab

Alhababy²,

Alfaifi

2016

Hellenic Plant Protection Journal

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Summary Qat leaves are chewed on a daily basis by approximately 10 million inhabitants of different countries. This study investigated the persistence of three insecticides most used in qat production, imidacloprid, acetamiprid and methomyl. These chemicals were applied separately on plots of ten qat trees each at the recommended application rates. Samples of qat leaves were collected separately at time 0 (1 h post-treatment) and 1, 3, 7, 12, 19, 26 and 37 days after application. The residues of the investigated pesticides were extracted and then quantified by liquid chromatography (LC-MS/MS). The half-lives of imidacloprid, acetamiprid and methomyl were 12.2, 11.7, and 5.1 days, respectively. Overall, our findings showed that imidacloprid and acetamiprid were more persistent than methomyl in qat leaves. Taking into account the maximum residue limits (MRL) in lettuce, due to lack of MRL in qat leaves, the residue concentrations were below MRL for imidacloprid 7 days after application, and 1 day after application for acetamiprid and methomyl.

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Section: Resultscontrasting

confidence: 81%

Persistence of imidacloprid, acetamiprid and methomyl in qat leaves

Al-Rajab

Alhababy²,

Alfaifi

2016

Hellenic Plant Protection Journal

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“…Studies indicated that tomato treated with methomyl should remain in the field about 15 days before harvesting in order to be consumed and marketed safely for human consumption. These results are in agreement with Malhat et al (2015) who calculated residue half-life of methomyl in tomato fruits as 1.34 days. Since methomyl has a systemic action, it can migrate inside the cuticle of the tomatoes and it may create different bonds with the inner media compounds of tomatoes (Rasolonjatovo et al 2017).…”

Section: Dissipation Of Methomyl Residues In Tomato Fruitssupporting

confidence: 93%

Journal of Plant Protection Research

El-Hefny,

Abdallah,

Helmy

et al. 2019

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Tomato is an economically important vegetable crop which is attacked heavily by insect pests leading to reduction of yield and quality of the fruits. Field experiments were carried out to investigate the dissipation of methomyl (a common insecticide) used mainly on tomato fruits. LC-MS/MS coupled with the QuEChERS method were used for the determination of methomyl. The results showed that the recovery using matrix-matched standards ranged from 87.8 to 101.3%, with relative standard deviation of 2.5 to 7.5%. Kinetics equation, Log R = log R 0 -0.434 Kt, was used to calculate the rate of degradation in tomato, soil and water. Residue half-life calculated using kinetic rate ranged from 1.95 to 1.63 days in tomato and soil, respectively. From the results it was concluded that tomato fruits can be safely harvested for consumption after 15 days of application based on estimated preharvest interval (PHI). It is advisable to re-estimate the PHI regularly owing to data from the EU and Codex.

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“…The observed DT50 of methomyl observed on spinach (3.11days) fits into the range of half-lives of methomyl on growing foliage (1-7 days) reported by [23,31]. Also, methomyl half-lives were 1.34 and 1.1867days on tomato fruits [3,20].…”

Section: Dissipation Of Chlorfenapyr and Methomyl In Spinachsupporting

confidence: 74%

Chlorfenapyr and Methomyl Deterioration on Spinach Plants and Their Residual Effects in Vitro on Egyptian cotton Leafworm (Spodoptera littoralis)

Fetoh¹,

Ramadan²,

Ali³

2021

JNFP

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Field trials conducted to determine the degradation of chlorfenapyr and methomyl insecticides in/on spinach leaves. Spinach plants sprayed with chlorfenapyr (Challenger Super™ 24% SC) and methomyl (Neomyl™ 90% SP) at the rates of 50 cm3/100 L water and 715 g/ ha, respectively. The QuEChERS method used for the extraction and clean-up of the samples. Residue amounts determined at 2 h, 2, 4, 6, 9, 13 and 16 days after application by UHPLC-UV. The mean of recovery percentages was 98.78 and 99.05 % for chlorfenapyr and methomyl, respectively. The initial deposits of chlorfenapyr and methomyl on/in spinach leaves, two hours after a single application of the insecticides were 23.17 and 235.37 mg/kg, respectively. The percentages of dissipation of chlorfenapyr were 37.68, 55.29, 69.45, 84.45 and 96.83% for 2, 4, 6, 9 and 16 days after application. The corresponding dissipation percentages of methomyl were 38.27, 56.01, 71.44, 84.34 and 97.81%. The rates of degradation (k values) were 0.212 and 0.223, while the corresponding half-life times (t0.5) were 3.27 and 3.11 days with chlorfenapyr and methomyl, respectively. It could be recommended that single application of chlorfenapyr on Spinach plants at the early ages followed by single application of methomyl at least 17 days before harvest.

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Degradation profile and safety evaluation of methomyl residues in tomato and soil

Cited by 17 publications

References 31 publications

Persistence of imidacloprid, acetamiprid and methomyl in qat leaves

Persistence of imidacloprid, acetamiprid and methomyl in qat leaves

Journal of Plant Protection Research

Chlorfenapyr and Methomyl Deterioration on Spinach Plants and Their Residual Effects in Vitro on Egyptian cotton Leafworm (Spodoptera littoralis)

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