Resumen
- Degradation and mineralization behavior of select-ed nematicides was studied in soil samples from fields culti-vated with banana, potato, and coffee. Degradation assays inmost of the studied soils revealed shorter half-lives forcarbofuran (CBF) and ethoprophos (ETP) in samples with ahistory of treatment with these compounds, which may havebeen caused by enhanced biodegradation. A short half-lifevalue for CBF degradation was also observed in a bananafield with no previous exposure to this pesticide, but with arecent application of the carbamate insecticide oxamyl, whichsupports the hypothesis that preexposure to oxamyl may causemicrobial adaptation towards degradation of CBF, an obser-vation of a phenomenon not yet tested according to the liter-ature reviewed. Mineralization assays for CBF and terbufos(TBF) revealed that history of treatment with these nemati-cides did not cause higher mineralization rates in preexposedsoils when compared to unexposed ones, except in the case ofsoils from coffee fields. Mineralization half-lives for soilsunexposed to these pesticides were significantly shorter thanmost reports in the literature in the same conditions.Mineralization rates for soils with a previous exposure to thesepesticides were also obtained, adding to the very few reportsfound. This paper contributes valuable data to the low numberof reports dealing with pesticide fate in soils from tropicalorigin.