Antagonismo de cepas de trichoderma spp. aisladas de suelos agrícolas de Galápagos a diferentes hongos patógenos.

Abstract

This research aimed to determine whether the strains of the fungus Trichoderma spp. present an antagonistic action against pathogenic fungi (Fusarium circinatum, Alternaria linariae, and Neocytelidium spp.). For this, the experiment followed a completely randomized bifactorial design scheme, where factor A consisted of 21 strains of Trichoderma spp. against factor B, which were eight strains of pathogenic fungi with three repetitions. The organisms were seeded using the dual culture technique between pathogens and antagonists in petri dishes with Potato Dextrose Agar medium. The diameter of each fungus was measured every 24 hours for four days until the antagonist grew above the pathogenic fungus and filled the growth medium. This determined the mycelial growth and the growth rate of both subjects. The level of antagonism was analyzed based on the Bell scale at 4-5 days of the growth and incubation process. These results were analyzed using the descriptive and inferential statistical analysis method with separation of means by Tukey's test at 5 %; as well as tables of the percentage of inhibition of mycelial growth were prepared. The strains with the best percentage of inhibition belonged to Trichoderma breve of code E and Trichoderma andinense of codes P, R and N with antagonism level 1 with 57%. The Trichoderma spp. completely overgrows the pathogen and completely covers the surface of the medium, followed by level 2 with 31%. The efficiency of Trichoderma to inhibit pathogens was corroborated. So, it is recommended to enhance the study of the antagonistic activity of Trichoderma in different substrates and different environmental conditions.