Resumo

SANABRIA VELAZQUEZ, Andrés Dejesús  e  GRABOWSKI OCAMPOS, Cristhian J.. Biological control of Rosellinia sp. causing of the sudden death of the macadamia (Macadamia integrifolia) with isolates of Trichoderma spp. Investig. Agrar. [online]. 2016, vol.18, n.2, pp.77-86. ISSN 2305-0683.  https://doi.org/10.18004/investig.agrar.2016.diciembre.77-86.

To evaluate the biological control exercised by native isolates of Trichoderma spp. on Rosellinia sp., responsible for the death of macadamia nut plants, two experiments were carried out at the Phytopathology Lab of the FCA-UNA, San Lorenzo, main campus and at the San Joaquín nursery, Caraguatay, Cordillera. For in vitro tests, 19 isolates of Trichoderma spp. were obtained from several macadamia growing plots in Paraguay. They were faced in matched crops with Rosellinia sp. to measure their antagonistic capacity, using a completely randomized design with five repetitions. The results allowed selecting the isolates GS18 (Itapua), GS13 (Central), GS10 (Cordillera) for their in vivo evaluation. For the second experiment, a completely randomized design was used. The treatments consisted on T1: Control (the pathogen only), T2: Trichoderma spp isolates mix. and T3: 1% Carbendazim having each one five repetitions. 12 months old Macadamia plants were treated with the Trichoderma spp isolates mix. After 2 weeks, the substratum of all plants was infested with Rosellinia sp. propagules, two more weeks were allowed to assure the establishment of the pathogen and then Carbendazim with 0,1% dose, was applied. In the control plants, it was observed a 53% incidence of disease, a 26% in the plants treated with the Trichoderma spp. mix and 7% in plants treated with Carbendazim. It is concluded that native isolates of Trichoderma spp. have a potential as Rosellinia sp .bio-control agents since they reduce the incidence of the disease in in vivo conditions.

Palavras-chave : antagonism; fungi; native isolates; bio-control agent; roots pathogen.

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