Evaluación in vitro de la capacidad antagonista de Trichoderma spp. y Clonostachys spp. frente a Neopestalotiopsis sp. en frutilla (Fragaria ananassa Duch.).

Abstract

The objective of this research work was to evaluate in vitro the antagonistic capacity of Trichoderma spp. and Clonostachys spp. against Neopestalotiopsis sp. in strawberry (Fragaria ananassa Duch.). The antagonism tests were carried out using the dual culture technique in Petri dishes with a PDA medium in which were placed a mycelium disc of 5 mm diameter for the antagonist and the pathogen. For this purpose, strains of Trichoderma spp., a strain of Clonostachys spp., and a strain of Neopestalotiopsis spp. were reactivated from the existing collection in the Phytopathology laboratory of the Faculty of Natural Resources of the ESPOCH. In the macroscopic characterization, cultural characteristics were registered, such as the color of the obverse, reverse, margin, texture, and pigmentation of the medium. Microscopic characterization was performed using the plate technique; therefore, data on fungal structures were registered. Finally, for molecular characterization, nucleic acids were extracted using the following process: mycelium extraction, physical lysis, chemical lysis, PCR, electrophoresis, and sequencing. The strains of Trichoderma spp. and Clonostachys spp. were identified and characterized morphologically and molecularly, corresponding to the following species: Trichoderma gamsii, Trichoderma longibrachiatum, Trichoderma harzianum, and Clonostachys rosea. The growth rates of the different strains were for Trichoderma spp. values from 15.72 mm/day to 8.73 mm/day, for Clonostachys spp. a value of 3.74 mm/day, and for Neopestalotiopsis spp. Np (1) a value of 7.86 mm/day. The percentage inhibition of mycelial growth of Neopestalotiopsis sp. exerted by the Trichoderma spp. strains were between 52.9% and 59.7%, while 30.1% was obtained for the Clonostachys sp. strain. The strains with the highest antagonistic efficacy against Neopestalotiopsis spp. were Trichoderma spp. MT (5) and MT (6), since they completely covered the pathogen, which is recommended for field evaluation.