The influence of tricyclazole on the production of phenolic precursors, glucose uptake and production of fungal mass of Fonsecaea pedrosoi was assessed in the presence of phenylalanine, sodium nitrate and tryptophan. Photocolorimetry was used for the quantitation of glucose and total phenol, and the dry weight method for biomass. The glucose uptake with phenylalanine was 99.85 x 10(3) mg/ml; with tryptophan, 99.88 x 10(3) mg/ml and with sodium nitrate, 99.90 x 10(3) mg/ml. Production of biomass: with tryptophan, 2.7 x 10(-1) mg; with sodium nitrate, 3.0 x 10(-1) mg and with phenylalanine, 3.4x 10(-1) mg. Tricyclazole induced higher phenol accumulation, lower glucose uptake, inhibition of melanin deposition on the cell and higher production and higher biomass production in relation to glucose uptake for all nitrogen sources tested under these conditions. A negative correlation between biomass production and glucose uptake was observed in the presence of secondary metabolism. (C) 2003 Elsevier Ltd. All rights reserved.