The growth of six Trichoderma spp. warm-weather strains (WWS) and temperate-weather strains (TWS) was determined by microcalorimetry at different temperatures from 10 to 35 degrees C. The metabolic heat production (p) and the apparent activation energy (E-a) were calculated. Significant differences among the strains were noted between 20 and 30 degrees C. The optimal growth temperature was 30 degrees C for strains TC74, T359, T479, and Th and was 35 degrees C for TC74M and T397. The p values were from 18 to 28 mW g(-1) dry weight of mycelium and 11-16 mW g(-1) of dry weight of mycelium for the WWS and TWS, respectively. The highest and lowest E-a values were observed for T479 (98 kJ mol(-1)) and Th (34 kJ mol(-1)), respectively. For WWS, the p value at the highest growth was directly related to antibiosis, and the E-a values were directly correlated to sclerotium parasitism. Both p and E-a were inversely related to sclerotium parasitism and pathogen growth inhibition, respectively. By contrast, the p value for TWS at maximal growth was inversely related to antibiosis while the E-a was directly related. Microcalorimetry was used to detect minute differences in metabolism heat among the Trichoderma strains, providing a rapid and accurate way to yield reproducible data. (C) 2010 Elsevier B.V. All rights reserved.