| Abstract: | Carbendazim was quantified spectrophotometrically in leaves, petioles, stems and pods from upper and lower halves of entire soybean plants following one or two foliar applications of thiophanate-methyl fungicide (1.1 kg ha?1 a.i.). Following the first application, the highest carbendazim concentrations occurred 1-4 days post-application and declined thereafter to undetectable (?0.12 mg kg?1) or barely detectable levels by day 26. The highest concentrations were in the leaves where carbendazim levels exceeded 3.5 mg kg?1 on day 4 and remained above 1.0 mg kg?1 until day 19. Concentrations in petioles and upper pods were initially in excess of 1.0 mg kg?1 and remained above 0.5 mg kg?1 for 12 days. In lower pods and in stems, concentrations were very low and often not detectable. Typically, concentrations were higher in samples from the upper half of the plant than in those from the lower half. A second application on day 18 resulted in carbendazim concentrations similar to those immediately after the first application; however, concentrations declined rapidly coincidentally with a period of rain. This decline may have been facilitated by poor fungicide uptake due to senescence of the plants. |
