Microbial secondary metabolites are produced during
microbial development and sporulation, and are among
the most important natural products used to inhibit
microbial growth (Sekiguchi and Gaucher 1977; Mapleston
et al. 1992; Stone and Williams 1992; Vinale et al.
2008a). The spectrum of secondary metabolites secreted
by Trichoderma is species- and strain-dependent and
includes volatile and nonvolatile antifungal substances
(Sivasithamparam and Ghisalberti 1998). In a recent
paper, we reported the isolation and characterization of
the major secondary metabolites produced by Trichoderma
harzianum T22 and T39, two commercial strains successfully
used as biopesticides and biofertilizers in
greenhouse and open field production (Vinale et al.
2006)