EFEITO IN VITRO DE FILTRADOS DE Trichoderma SOBRE Pratylenchus brachyurus

Abstract

The purpose of this work was to evaluate mortality and constitute a selection of Trichoderma sp. effective antagonists in the biological control of Pratylenchus brachyurus. subjected to different species of Trichoderma filtrates. The experiment carried out in vitro was analyzed after 24 hours, with 11 treatments, 10 of which were Trichoderma isolates and an untreated control. The metabolites of Trichoderma sp. were obtained from the growth of the fungus (5 discs/5mm) in parboiled rice (55g/bottle), moistened and autoclaved, for 7 days. After growth, the substrate was washed with 50 mL of 0.9% NaCl, and the content was filtered and centrifuged (10° C, 7,000g/10 min), obtaining the conidia (pellets) and the metabolites of Trichoderma (filtered). In test tubes, 200 J2 of P. brachyurus, concentrated in 1.0 mL, and 2.0 mL of the suspension corresponding to each treatment were added. The control received 2.0 mL of distilled water. Mortality was evaluated according to Chen & Dickson (2000). The isolates T. asperellum TQQ and T. harzianum 8404 showed the highest P. brachyurus mortality rates, reaching 82.04% and 65.46% respectively. On the other hand, the isolates T. asperellum T00, and T. harzianum TST, did not show significant difference in relation to the control, with an average of 27.16%. In summary, this study proved that the metabolites produced by Trichoderma fungi had a direct effect on nematode mortality, showing promise in the production of metabolites with potential application in the biological control of P. brachyurus.