The antagonist effects of thirty one Trichoderma strains isolated from different regions of México on
Phytophthora capsici Leonian were evaluated. In this study, both fungal species were confronted on
petri dishes with agar-potato-dextrose (PDA) medium. Thirteen out of thirty one Trichoderma strains
showed a good competition level, covering the petri dish area completely. Volatile compounds were
observed in twenty four out of thirty one Trichoderma strains which inhibited to P. capsici in a range
from 4.3 to 48.8%. In addition, it was observed that the supernatant of fourteen out of thirty one
Trichoderma strains showed inhibitory effects on P. capsici. Thirteen of the fourteen Trichoderma
strains were identified at the specie level using sequencing of 18S rDNA. Eleven of those strains were
identified as T. asperellum, one as T. hamatum and one as T. rossicum.