RESIDUES OF THIAMETHOXAM AND CHLORPYRIFOS ON OKRA IN RELATION TO THEIR EFFECTS ON SOME INTERNAL QUALITY PARAMETERS AND ELEMENTS IN FRUITS. | ||
| Journal of Productivity and Development | ||
| Article 10, Volume 21, Issue 3, August 2016, Pages 349-367 PDF (587.13 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jpd.2016.42276 | ||
| Author | ||
| Aly Shalaby* | ||
| Plant Protection Department, Faculty of Agriculture, Zagazig University, Egypt | ||
| Abstract | ||
| The present work was conducted to study the residues of two insecticides on okra plant. Thiamethoxam (Actara 25% WG) and chlorpyrifos (Dursban 48% EC) were sprayed at mature stage. Fruits and leaves samples were collected at 2 hrs to 15 days after application. QuEChERS method was used for extraction and clean-up and analyzed using HPLC and GC for thiamethoxam and chlorpyrifos, respectively. Results revealed that, okra leaves remained higher initial amounts than fruits by about 382.52% and 893.48% of thiamethoxam and chlorpyrifos, respectively. Loss percentages of initial deposits were higher in okra fruits than leaves. The half-life (t½) values of thiamethoxam and chlorpyrifos were 2.09, 3.16 and 1.59, 2.57 in okra fruits and leaves, respectively. Data indicated that okra fruits could be consumed safely after 15 days of treatment with thiamethoxam, washing or boiling of okra fruits (2 min) during the first 6 days after spraying did not alter the PHI value, while in case of chlorpyrifos washed and unwashed okra fruits could be used safely after 6 days and no safety interval was needed after boiling okra fruits for 2 min. The removal percentages of thiamethoxam and chlorpyrifos residues by washing ranged between 9.39 - 46.23%; 5.88 – 21.40%, while the corresponding values due to boiled the okra fruits 2 min ranged from 74.77 to 89.09%; 84.63 - 87.51%. Residues of thiamethoxam and chlorpyrifossignificantly decreased total soluble sugar%, glucose mg/100g, acidity %, total soluble solids %, ascorbic acid mg/100g, protein content%, β-carotene%, protein% and dry matter % of fresh treated okra fruits comparing with the control during the tested period. Concerning the trace / nutrients elements thiamethoxam significantly reduced the mean values of N%, P%, K%, Mn% and Ca% and increased the mean amounts of Fe% and Zn in treated okra fruits. Chlorpyrifos significantly reduced the mean levels of N%, P%, K%, Fe% and Ca% and increased the mean amounts of Mn% and Zn in okra fruits. These effects were more pronounced in thiamethoxam treatment. Therefore, attention must be given to the use of thiamethoxam especially during the mature stage. Conclusively, okra fruits treated with the neonicotonoied insecticide thiamethoxam needed a long interval to reach the maximum residue limits. Also, obtained data revealed that its residues were more effective in some quality attributes as well as some trace and nutrient elements than that the organphosphorus chlorpyrifos. Therefore, special care must be given to the use of this insecticide especially at the mature stage of okra plants. | ||
| Keywords | ||
| thiamethoxam; chlorpyrifos; QuEChERS; okra; residues; quality parameters | ||
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