Resumo

RIVERA-MENDEZ, William; MENESES-MONTERO, Karla; ZUNIGA-VEGA, Claudia  e  BRENES-MADRIZ, Jaime A.. Trichoderma’s antagonism in front of the pathogen Stromatinia cepivora in onion crops. Tecnología en Marcha [online]. 2016, vol.29, suppl.3, pp.22-30. ISSN 0379-3982.  http://dx.doi.org/10.18845/tm.v29i7.2702.

In Cost Rica, the onion crop is an important source of income for small and middle size farmers. The fungus Stromatinia cepivora, it has worldwide importance and specifically in Cartago (Granados, 2005, 2013; Metcalf et al., 2004). The control of S. cepivora is not easy, there are few resistant and commercial onion varieties and there are not many fungicides for this control. Due to these factors, biological control is a good option against white rot. Trichoderma is a soil fungal genus that includes species widely used as biological control agents in agriculture. The objective of the research was to evaluate the antagonism in vitro and in the field of Trichoderma isolated from producing areas in Cartago, Costa Rica, against S. cepivora. Isolation and characterization studies were conducted from onion bulbs with symptoms of the disease. Then antagonism essays were developed to show the effectiveness of selected strains. The strain identified as T. asperellum was antagonistic against S. cepivora, both in vitro and in the field test. This effectiveness was determined by the interaction between a specific antagonistic strain and a specific pathogenic strain. For the application of this control strategy, it is necessary to emphasize to farmers the importance of the actions to maintain the health and the preparation of the soil, which allow for the reduction in the inoculum levels, an essential factor for obtaining good crop yields.

Palavras-chave : Trichoderma; Stromatinia cepivora; onion; biocontrol.

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