Potato response to simulated tank contamination of three sulfonylurea herbicides was evaluated in a pot study in Águas da Prata, São Paulo, Brazil. The purpose of the trial was to study the effect of subdoses of the herbicides metsulfuron-methyl, nicosulfuron and sulfometuron-methyl on yield and tuber quality of two potato cultivars. Metsulfuron-methyl, nicosulfuron and sulfometuron-methyl were applied in post-emergence on 'Atlantic' and 'Lady Rosetta' cultivars at rates corresponding to 0, 0.00001, 0.0001, 0.001, 0.01, 0.1 and 1 times the recommended rate. At harvest, root fresh weight, number and fresh weight of normal and malformed tubers and total yield of tubers were determined. None of the rates applied killed the potato plants.Sulfonylurea application affected tuber development causing anomalies but these also varied with products and rates. 'Atlantic' yield losses were greater than 'Lady Rosetta's yield losses when metsulfuron-methyl was applied. 'Lady Rosetta' tuber yield was more sensitive than that of'Atlantic to nicosulfuron and sulfometuron-methyl.
Solanum tuberosum; metsulfuron-methyl; nicosulfuron; sulfometuron-methyl
