Resumo

VARGAS HOYOS, Harold Alexander  e  GILCHRIST RAMELLI, Elizabeth. Bioavailability of Trichoderma asperellum over time in Andisol soil in laboratory and field conditions. Rev. Lasallista Investig. [online]. 2015, vol.12, n.1, pp.72-80. ISSN 1794-4449.

Introduction. Trichoderma asperellum strain T109 has shown great antagonism activity in vitro against phytopathogenic fungi. However, it is necessary the real understand of this strain into spatial organization in soil under in vitro and field conditions to know the population density. Objective. The aim of this study was to evaluate different inoculum concentrations and frequencies of application in Trichoderma asperellum T109 bioavailability. Materials and methods. Spore suspensions containing 1x10⁶ and 1x10⁸ conidia.mL^-1, were evaluated under controlled laboratory and field conditions, with different application times. We used the technique of Petri plate count for determination of CFU.g^-1 of soil. Results. The T109 bioavailability was affected by the frequency of application and highly significant (p<0.001) for the initial concentration of inoculum. The last sampling under in vitro conditions showed that the concentration of 1x10⁶ conidia mL^-1 was significantly different (p<0.001) when compared to 1x10⁸ conidias.mL^-1, yielding maximum value of CFU.g^-1 of soil for every 4 days of application. For field conditions, we obtained significant differences (p<0.001) when the concentration of 1x10⁸conidias mL^-1 and application of 7 days were tested concomitantly. Conclusions. We can determine that the population density of T. asperellum T109 is important in the establishment of the fungus in the soil.

Palavras-chave : biocontrol; inoculums; concentrations; application rate; population density.

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