Rate of disappearance of fenitrothion on stored brown rice and paddy
2000
Gragasin, M.C.B. | Motoyama, N. (Bureau of Postharvest Research and Extension, CLSU Compound, Munoz, Nueva Ecija 3120 (Philippines))
The dissipation rate of fenitrothion applied on stored brown and paddy was investigated to estimate the length of time that this compound retains its residual activity as well as to understand the mechanisms of dissipation. A continuous decrease in the total fenitrothion residue was observed as storage time progressed at all temperature settings used. In general, the rate of dissipation was dependent on the storage temperature, being lowest at 15 deg C and highest at 35 deg C. There was no difference on the patterns of dissipation of fenitrothion applied on the glass surface and that on brown rice regardless of the storage temperature, suggesting that the dissipation was of spontaneous nature and not biologically mediated one. In contrast, a significantly faster dissipation rate was observed when fenitrothion was applied on normal paddy (paddy that do not undergo any treatment) as compared to that applied on the other surfaces. Sterilization of paddy, however, markedly affected the dissipation rate, resulting in a higher residue level of fenitrothion. These results suggest that microorganisms present on the seed coat of paddy maybe involved on the degradation of fenitrothion and thus contributing to a faster dissipation of this insecticide
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