## 3 Results and Discussion
### Identification of VOCs and nVOCs
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Compound (VOCs)** & \multicolumn{2}{c}{**Strains**} \\ \cline{2-3}  & _Trichoderma asperellum_ & _Trichoderma atrovide_ \\ \hline _Pyrazines_ & & \\ Trimethyl pyrazine & \(0.09\pm 0.01\) & \(0.43\pm 0.03\) \\ Tetramethyl pyrazine & \(4.81\pm 0.04\) & \(56.79\pm 0.29\) \\
2,3,5-trimethyl-6-ethylpyrazine & \(0.45\pm 0.01\) & \(1\pm 0.06\) \\
2,3,5-trimethyl-6-propylpyrazine & \(0.14\pm 0\) & \(0.14\pm 0.01\) \\
2-methyl-3,5-diethylpyrazine & ND & \(0.74\pm 0.02\) \\ Trimethyllischobutylpyrazine & ND & \(0.86\pm 0.07\) \\
2,3-dimethyl-5-(1-propenyl)pyrazine & \(0.04\pm 0\) & ND \\ \hline _Esters_ & & \\ Ethyl acetate & \(0.62\pm 0.01\) & \(0.46\pm 0\) \\ Ethyl isobutyrate & \(0.15\pm 0.02\) & ND \\ Isobutyl butanoate & \(0.22\pm 0.01\) & ND \\ Ethyl B-hydroxybutyrate & \(0.11\pm 0.01\) & \(0.22\pm 0\) \\ Isoamyl 2-methylpypenanoate & \(0.18\pm 0.01\) & ND \\ Butyl isobutyrate & \(0.10\pm 0\) & ND \\ Ethyl 3-acetoxybutanoate & ND & \(0.34\pm 0.01\) \\ \(\beta\)-phenylethyl formate & \(0.14\pm 0.01\) & ND \\ Ethyl benzoacetate & ND & \(1.16\pm 0.09\) \\
2-phenethyl acetate & \(1.15\pm 0.05\) & ND \\ Pentanoic acid, oct-4-yl ester & ND & \(0.66\pm 0.07\) \\ Isobutyl phenylacetate & ND & \(0.08\pm 0.01\) \\ \(\alpha\)-phenylethyl butyrate & \(0.41\pm 0.01\) & ND \\ Butyl isobutrate & ND & \(0.26\pm 0.02\) \\ \hline _Others_ & & \\
2,2-diphenyl-2H-1-benzopyran & \(0.22\pm 0.02\) & ND \\ Trimethyloxazole & ND & \(0.83\pm 0.03\) \\
2-pentyl furan & \(0.19\pm 0.01\) & ND \\ Methyl hydroxylazidolize & \(0.08\pm 0\) & ND \\
5,6,7,8-tetrahydro-2-methyl-4H-chromen-4-one & \(0.23\pm 0.01\) & \(1.38\pm 0.08\) \\ Methyl 3,4-di-O-acetyl-2-O-methylofurofuranoside & \(0.16\pm 0.01\) & ND \\
1,3-di-tert-butylbenzene & \(0.20\pm 0.02\) & \(0.48\pm 0.18\) \\
2,4-dimethyl-3-acetylpyrrole & ND & \(0.29\pm 0.04\) \\
6,7-dimethyl-1,2,3,5,8,8-hexahdenophthalene & \(0.22\pm 0.03\) & ND \\
3-methylhexyl isothianate & ND & \(1.39\pm 0.10\) \\
6-pentyl-alpha-pyrone & \(42.66\pm 0.15\) & \(0.26\pm 0\) \\ \(\alpha\)-Himchadiene & \(2.14\pm 0.13\) & \(0.61\pm 0.01\) \\ \(\alpha\)-Zingiberene & \(5.86\pm 0.01\) & \(2.67\pm 0.14\) \\
1-hydroxy-2,4-di-tert-butylbenzene & \(2.50\pm 0.04\) & \(6.17\pm 0.04\) \\ Butylated hydroxytoluene & \(0.58\pm 0.01\) & \(1.66\pm 0.11\) \\ \(\alpha\)-Sesquiphellandrene & \(6.60\pm 0.07\) & \(2.43\pm 0.05\) \\ Nefold & ND & \(0.86\pm 0.01\) \\ Cedrene & \(0.34\pm 0.08\) & ND \\
6,7-dihydro-2-trans-farnesol & \(0.63\pm 0.04\) & ND \\
1,2,4,4,6-pentametethyl-1,4-dihydropyridine-3,5-dicarbonitrile & ND & \(1.19\pm 0.01\) \\ Lead & \(0.95\pm 0.02\) & \(3.04\pm 0.36\) \\ Phenol, 2-(1,1-dimethylethyl)-4-(1-methyl)-1-phenylethyl & \(0.26\pm 0\) & \(1.15\pm 0.76\) \\ \hline \hline \end{tabular}  
* Not Determined.  
\end{table} 
Table 4: _Cont._it exerts antifungal properties, reducing the mycelial growth rate of _Rhizoctonia solani_ and _F. oxysporum_ f. sp. _Iycopersici_[36]. Finally, [PERSON] et al., 2008 [37] reported that 6-PP has a growth-promoting effect on tomato seedlings which compared to control plants had a more extensive and vigorous root system. Tetramethylpyrazine, also known as Lanzorite, is a compound belonging to the alkylpyrazines with the characteristic nutty and roasted flavor [38]; it has been found in fermented cocoa beans and soybeans fermented by _Bacillus_ spp. [39; 40]. There is no report in the literature on this substance produced by _Trichoderma_ spp. Pyrazines are known as substances with antifungal and nematicidal activity [41; 42], previous studies have shown that tetramethylpyrazine inhibits the growth of _Moniliophthora perniciosa_ and _F. oxysporum_ f. sp. _lactucae_[43]. The analysis of the nonvolatile organic compounds (nVOCs) of the culture filtrates of _Trichoderma_ strains tested, _T. asperellum_ IMI 393899 and _T.