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- Toxicity of Carbofuran to the Brown Planthopper, Nilaparvata lugens...
Toxicity of Carbofuran to the Brown Planthopper, Nilaparvata lugens (Stal) and Its Metabolism in the Rice Plant
Thesis Abstract:
Experiments were conducted to determine the toxicity of carbofuran to the brown plathopper and to evaluate its metabolism in the rice plant under sunlight and laboratory conditions at different temperatures and light intensities.
Carbofuran was found to be more toxic to treated plants kept in the laboratory then to those exposed to sunlight. The toxicity of carbofuran decreased with increasing temperature and light intensity the decrease being faster at higher temperature than at higher light intensity.
Carbofuran was metabolized by the rice plant to 3-hydroxy carbofuran and rapidly converted to 3-keto carbofuran. This, in turn, was converted to three unknowns that were speedily conjugated by the rice plant to form glycosides. When exposed to sunlight and different temperatures, carbofuran, 3-hydroxy carbofuran and 3-keto carbofuran we3re decomposed into their corresponding phenols. Decomposition rate was affected more by temperature than by sunlight.
The rapid loss of toxicity to brown planthoppers was associated with the rapid degradation of carbofuran under sunlight or at hight temperature and light intensity. This suggests that temperature and irradiation by sunlight are probably the two most important contributing factors to the degradation of carbofuran to nontoxic products in the field.
