**Author details**

Harman [43], argues that *T. harzianum* stimulates the growth of plants by producing metabolites that promote developmental processes, which allow greater root development and absorbent hairs, which favors the mobilization of nutrients in the soil, thus improving nutrition and water absorption; also accelerates the decomposition of organic matter and minerals [44].

164 Fusarium - Plant Diseases, Pathogen Diversity, Genetic Diversity, Resistance and Molecular Markers

The native strains of *Trichoderma* spp. presented higher biomass (green), emphasizing the treatment based on *T. harzianum*, which showed a root height of 10.58 cm and a green biomass of 0.97 g; denoting a significant increase in comparison with the control "**Figure 4**", which showed an average root height of 4.53 cm, and a green biomass of 0.19 g, while the treatment inoculated with the *F. oxysporum* strain Fo-A, presented the lowest root height averages, with

Plants affected by *F. oxysporum* reduce their growth due to the pathogen's ability to colonize roots, which prevents proper nutrition of the seedling and leads to death, causing losses in the

The evaluation of Mexican strains of *Trichoderma* spp. and its antagonistic effect on *F. oxysporum* on tomato seedlings (*L. esculentum* Mill) was determinant to verify their potential for biological control in a crop of great importance in the economy and the country's food.

The *T. harzianum* strain presented the highest growth rate with a mean of 1.25 cm/day, proving to be the most aggressive strain to control *F. oxysporum* with a development rate of 3.80 mm/day.

The three native strains of *Trichoderma* spp. present inhibition of radial growth on the Fo-A (*F. oxysporum*) strain, with *T. harzianum* being the most antagonistic (81.50%), in addition, the results of the interaction of the paired dual cultures to *F. oxysporum*, was very heterogeneous and highly significant statistic differences, where the *Trichoderma* isolates showed a zone of visible overgrowth with the *F. oxysporum* hyphae, which shows more aggressiveness on the

The efficacy shown by the native strains of *Trichoderma* spp. evaluated in this study against *F. oxysporum*, applied to tomato seedlings (*Lycopersicon esculentum* Mill), showed that *T. harzianum* obtained higher height, greater stem thickness and greater production of dry biomass, likewise, the treatment inoculated with *F. oxysporum* obtained the highest incidence (83%) and the lowest survival (17%) of germination in greenhouse conditions.

The authors thank the Vicerrectoría de Investigación y Estudios de Postgrado and to Instituto de Ciencias from BUAP for funding this research project, likewise, producers of the region Tetela de Ocampo, Puebla-México, for the facilities to carry out the present investigation.

3.70 cm and 0.18 g in green biomass.

producer in the first stage of tomato crop.

part of the antagonistic fungus.

**Acknowledgements**

**4. Conclusions**

Omar Romero Arenas1 , Jesús Francisco López Olguín1 , Dionicio Juárez Ramón<sup>1</sup> , Dora Ma. Sangerman-Jarquín<sup>2</sup> , Conrado Parraguirre Lezama1 , Primo Sánchez Morales<sup>1</sup> and Manuel Huerta Lara1 \*

\*Address all correspondence to: batprofesor@hotmail.com

1 Centro de Agroecología, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla (BUAP), México

2 Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), Campo Experimental Valle de México, Carretera Los Reyes-Texcoco, Texcoco, Estado de México, México
