This research was throughout 2018-2020, filamentous fungi of agricultural importance were isolated from the Cerro Las Tetillas, located in the municipality of Salvatierra, Guanajuato. The hill was divided into three strata: upper, middle and lower. Two hundred soil samples were taken at depths of 0-15 and 15-30 cm. These were processed in the biology laboratory, belonging to the Higher Technological Institute of Salvatierra. Two isolation techniques were used: direct seeding and serial dilutions, over Petri dishes with potato dextrose agar culture medium and 100 mg of streptomycin to control bacteria. One hundred and thirteen axenic strains corresponding to 16 genera identified from “Cerro Tetillas” were obtained. At the upper stratum, 13 genera were identified, while in the middle and lower strata, nine genera were identified in each one of them. The diversity of soil fungi found in the different strata of the hill may be due to physicochemical characteristics of soil, native vegetation, interaction and abundance of soil fungi species, human disturbance and rain runoff.

Using natural extract of epazote (Chenopodium ambrosioides L.), has shown to control phytopatogenic fungi (P. Aguilar et al., 2013; y J. Black Solis et al., 2017). One mililiter of ethanolic extract at concentrations of 25%, 50%, 100% diluted on sterile distilled water (V:V) has been used to inhibit micelial developement of Fusarium oxysporum, and Fusarium solani, added to PDA Petri dish under a completely randomized experimental design, a statistical analysis was carried out by means of an ANOVA and comparison test of means with Tukey´s multiple range. After eight days of incubation, the outstanding inhibit effect has been observed with 100% and the average diameter of colonies was 62 mm., has been measured on both fungi species. In contrast, 62 mm., and 61 mm., was observed on F. oxysporum and F. solani respectively, and a statistical effect was observed (p≤0.05). With 25% and 50%, micelial inhibit developement has been measured, but no statistical differences between concentrations has been calculated (p≥0.05) for both fungi. The results suggest that ethanolic extract of epazote could be used to control both phytopathogenic fungi.