Efecto de especies de trichoderma en el crecimiento de la microbiota asociada al cáncer de tronco de Gmelina arborea roxb. (melina) en Pedro Vicente Maldonado

Abstract

The causal agent of trunk cancer in Melina plantations in Ecuador is unknown. However, this disease is affecting the performance of the Melina plantations of the company Endesa S.A. on the Pitzará property, which is located in the Pedro Vicente Maldonado canton. Therefore, the objective of the present investigation was to evaluate the effect of six Trichoderma species on the growth of the microbiota associated with Melina trunk cancer (Gmelina arborea Roxb.) in Pedro Vicente Maldonado. The methodology used had a field phase and a laboratory phase, where disease incidence and severity were analyzed in two plots for each stand to be sampled. Samples of woody stems of symptomatic trees were obtained, and the isolation of the microorganisms from the collected samples, the cultural, morphological, molecular, and pathogenic characterization was carried out to verify their pathogenicity in Melina plants. Subsequently, confrontations were carried out between pathogenic agents (Fusarium solani and Nectria pseudotria) and biological agents (Trichoderma species) to evaluate the mechanisms of action of the different Trichoderma species. Fusarium solani and Nectria pseudotrichia were identified as pathogenic agents associated with trunk cancer in melina plantations, as well as Trichoderma resei as the best antagonist for both pathogens in the variables of competition for space and nutrients, percentage of inhibition, and mycoparasitism. It is concluded that there are various levels of antagonism of Trichoderma spp. against strains of Fusarium solani and Nectria pseudotrichia. These agents caused the disease called trunk cancer in Melina plantations on the Pitzará property of Endesa S.A.