PERSISTANCE OF CHROMAFENOZIDE AND METHOXYFENOZIDE ON AND IN TOMATO FRUITS AND ON FILMS EXPOSED TO ULTRA - VIOLET AND SUNLIGHT | ||||
| Journal of Plant Protection and Pathology | ||||
| Article 6, Volume 31, Issue 6, May and June 2006, Page 3963-3972 PDF (2.87 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jppp.2006.235232 | ||||
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| Authors | ||||
| Dalia A. Barakat,; S. A. EI- Mahy | ||||
| Economic Entomology and Pesticides Dept., Faculty of Agriculture, Cairo University, Giza, Egypt. | ||||
| Abstract | ||||
| The persistence of chromafenozide and methoxyfenozide in and on tomato fruits under filed conditions during 2006 season was studied. Chromafenozide (Virtu 5% SC) and methoxyfenozide (Runner 24% SC) were sprayed on tomato fruits at their recommended rates of application, 400 ml and 150 mUfed, respectively. The most suitable method for extracting chromafanozide and methoxyfenozide was the use of methylene chloride. The percent recoveries were 92 and 89 for chromafenozide and methoxyfenozide, respectively. The initial deposit of methoxyfenozide on the tomato fruits (0.559 ppm) was higher than that of chromafenozide (0.123 ppm). The data show that washing tomato fruits at zero time and at different intervals after application of methoxyfenozide removed a reasonable quantity of residues, from 42.1 to 51.2% of the initial total amount. The corresponding values for chromafenozide ranged from 8.2 to 44.5%. This clearly demonstrated that after application of chromafenozide to tomato, it is either absorbed or bound to the surface or due to the solubility in waxy layer so tightly that it can not be removed by simple washing, whereas, in the case of methoxyfenozide its absorption or binding to the tomato surface was lower than chromafenozide. Methoxyfenozide was more persistent than chromafenozide when exposed to sunlight. However, methoxyfenozide degraded more rapidly than chromafenozide during the first five hours. The half-life times of chromafenozide and methoxyfenozide were 14.3 and 26.2 hours, respectively after exposure to sunlight. The results also indicated that the photodecomposition rate of methoxyfenozide was more rapid than chromafenozide in the first 6 hours after exposure to UV-light with 14.1, 28.5 and 44.8% loss after 1, 3 and 6 hours. while the corresponding amounts for chromafenozide were 8.0, 19.4 and 44.6% loss, respectively. Statistically, the half-life of chromafenozide and methoxyfenozide as dry thin films exposed to UV light were 6.8 and 8.0 hours, respectively. | ||||
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