RESUMEN
<b>Background and Objective:</b> Fungi of the genus <i>Trichoderma </i>have high versatility in the control of different plant diseases. Among the main mechanisms of action of these fungi against phytopathogenic fungi, the production of Volatile Organic Compounds (VOCs) is mentioned. These compounds are said to inhibit the mycelial growth of various fungal pathogens. The objective of this work was to evaluate the <i>in vitro</i> inhibition of the mycelial growth of <i>Sclerotinia sclerotiorum </i>by VOCs from six <i>Trichoderma </i>strains in different stages of development of the biocontrol agent. <b>Materials and Methods:</b> In this work, the <i>in vitro </i>evaluation of the mycelial growth of the phytopathogen <i>S. sclerotiorum </i>by VOCs from six <i>Trichoderma </i>strains was carried out: <i>T. koningiopsis </i>(CEN1386), <i>T. asperelloides </i>(CEN1397), <i>T. longibrachiatum </i>(CEN1399) <i>T. lentiforme </i>(CEN1416), <i>T</i>. <i>perbedyi</i> (CEN1389) and <i>T. azevedoi</i> (CEN1241). Observations were made at different stages of antagonist development: mycelial Growth Phase (GP), Sporulation Phase (SP) and paired with the Pathogen Phase (PP). Besides, the sporulation of the tested strains was quantified. <b>Conclusion:</b> In all experimental conditions, the VOCs produced by the CEN1241 strain showed a greater inhibitory effect, although the inhibition was less evident when the cultures of <i>S. sclerotiorum </i>were exposed in the GP phase of the antagonist. Greater sporulation was observed with <i>T. lentiforme</i> (CEN1416), a fact not related to a better ability to inhibit <i>S. sclerotiorum</i>, by VOCs.
