The fungus Fusarium circinatum Nirenberg & O'Donnell causes pine pitch canker, an important disease for conifers worldwide. F. circinatum was first detected in Chile in 2001 and to date is present in nurseries and clonal hedges from Libertador General Bernardo O'Higgins Region to Los Ríos Region. The purpose of this study was to evaluate the potential of Trichoderma spp. and Clonostachys spp. strains to control F. circinatum in Pinus radiata D. Don seedlings in the absence of other effective control methods. Eighty-one Trichoderma spp. and Clonostachys spp. strains were evaluated through in vitro assays to determine their ability to act as antagonists of F. circinatum and 21 strains were tested for their ability to reduce post-emergence mortality and increase P. radiata survival under greenhouse conditions. During in vitro experiments, 15 strains of Trichoderma inhibited mycelial growth of the pathogen by more than 60% and one strain of Clonostachys showed parasitism of F. circinatum hyphae. Greenhouse experiments showed no control of the disease when the antagonists were added to substrate after the pathogen. However, when the antagonists were added before the pathogen, four strains (Clonostachys UDC-32 and UDC-222 and Trichoderma UDC-23 and UDC-408) reduced post-emergence mortality between 80 and 100%. Among these strains, only Clonostachys UDC-222 significantly increased the survival of P. radiata seedlings. These results showed that Clonostachys UDC-222 has the potential to be used as a biocontrol agent against F. circinatum in the production of P. radiata plants.

SUMMARYThe genus Colletotrichum comprises several species in cryptic complexes that cannot be easily recognizable using morphological and cultural characteristics. As a consequence of the lack of morphological characters suitable for identification, DNA sequence analyses are now typically used as the primary basis in diagnosis and description of new species of Colletotrichum. In this study, based on a multi-locus phylogeny analysis, C. pyricola was identified on leaves of Embothrium coccineum in Chile, corresponding to the first report of this fungus in the country. Colletotrichum pyricola is a member of the C. acutatum complex, morphologically sharing features with several species of this group, being necessary the combination of morphological and molecular data for its identification. Species of Colletotrichum cause diseases in a wide range of hosts, making it important to establish an accurate diagnosis of the species for plant pathology or quarantine purposes.Key words: Colletotrichum pyricola, Embothrium coccineum, anthracnose, morphological characteristics, multi-locus analysis. RESUMENEl género Colletotrichum comprende varias especies crípticas dentro de complejos que no pueden ser fácilmente identificables usando características morfológicas y culturales. Como consecuencia de la falta de caracteres morfológicos adecuados para la identificación, los análisis de secuencias de ADN son comúnmente usados, en la actualidad, en el diagnóstico e identificación de nuevas especies. En este estudio, mediante análisis filogenético multi-locus se identificó a C. pyricola en hojas de Embothrium coccineum, correspondiente a primer reporte de este hongo en Chile. Colletotrichum pyricola pertenece al complex de C. acutatum, morfológicamente comparte características con varias especies de este grupo, siendo necesario la combinación de datos morfológicos y moleculares para su identificación. Especies de Colletotrichum causan enfermedades en un amplio rango de hospederos, haciendo importante establecer con precisión el diagnóstico de la especie para fines fitopatológicos o de cuarentena.