Antagonismo in vitro de Trichoderma spp. nativo sobre Fusarium oxysporum

Abstract

The evaluation of new Trichoderma strains against plant-pathogenic fungi will enable the development of sustainable biocontrols, thereby reducing the use of agrochemicals. Therefore, the objective of this research is to identify a local strain with biocontrol capabilities and in vitro antagonistic potential against Fusarium oxysporum. At the UTEQ laboratory, pure cultures of Trichoderma spp. (from banana soil) and F. oxysporum (from banana roots) were isolated and purified on PDA medium. Both were characterized morphologically, both microscopically and macroscopically. Finally, using the dual-challenge technique at 27 °C, mycelial growth and antagonistic activity were evaluated based on the percentage of invasion. The study assessed the antagonistic activity of Trichoderma spp. against F. oxysporum over a period of 192 hours. Trichoderma spp. demonstrated a higher rate of mycelial growth, increasing from 10 mm to 75 mm, compared to F. oxysporum, which grew from 10 mm to 40 mm. This growth rate allowed it to rapidly colonize the culture medium and compete for space and nutrients. In the dual culture assay, direct contact and suppression of the plant pathogen occurred at 120 hours. At 192 hours, Trichoderma spp. outcompeted and invaded the F. oxysporum colony, reducing its visible mycelium to 20 mm through mycoparasitism and direct inhibition. It can be observed that the native Trichoderma spp. has a HIGH antagonistic effect, managing to invade up to three-quarters (3/4) of the colony of the plant pathogen F. oxysporum, with the presence of dense hyphae, and can therefore be considered a potential biocontrol agent