Biocontrollers in the management of yam dry rot nematodes

• Autor(a) principal: Cecilia Ramirez
• Data de Publicação: 2021
• Outros Autores: Alverlan da Silva Araújo, Gilson Moura Filho, Fernando da Silva Rocha, Marylia Gabriella Silva Costa, Maria de Fátima Silva Muniz
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFMG
• Texto Completo: https://doi.org/10.17648/diversitas-journal-v6i1-1572; http://hdl.handle.net/1843/53428
• topic: Dioscorea spp; Scutellonema bradys; Pratylenchus sp.; management; Biocontrollers; Inhame-do-ar; Nematoda

One of the main diseases affecting yam crops (Dioscoreaspp.) in Brazil is the dry rot caused by Scutellonema bradys, Pratylenchus brachyurus and P. coffeae nematodes. The use of biological control agents is an auspicious procedure which has been tested in order to reduce losses by pathogens. The objective of this work was to evaluate the nematicidal activity in vitroand in vivoof commercial biological products on yam dry rot nematodes. Products based on Trichoderma harzianum(2.0 x 109conidiamL-1) at dosages of 1.5 and 2.0 L200 L-1of water; Bacillussubtilis 20% -1.0 x 1011cfug-1+ B. licheniformis 20% -1.0 x 1011cfug-1at 100 and 150 g100 L-1; B. subtilis200 gkg-1+ B. licheniformis 200 gkg-1at 130 and 200 g100L-1;combination of rhizobacteria including Bacillusspp. and organic carbonat 5L and 7L100L-1; and the control (distilled water), were tested in in vitroassays on S. bradys orPratylenchussp. In experiments performed under greenhouse conditions, healthy seed tubers were planted in sterilized soil and thirty days later the soil was infested with a suspension of 1,000 specimens of a mixed population ofS. bradys and P. coffeae. Then, after 30 days products based onB.subtilis 20% + B. licheniformis 20% -150 g100L-1; T.harzianum2 L200L-1and rhizobacteria + organic carbon 7 L100L-1, at 100 mL per pot, were applied to the soil. Three months after planting, the percentage of sprouting of the seed tubers was evaluated and in the fifth month, the nematode population densities were determined. The sprouting of seed tubers wasof 100% in all treatments. Bacillussubtilis 20% + B. licheniformis 20% andT.harzianumcaused 89% and 61% mortality in S. bradysrespectively, at the highest concentrations. In specimens of Pratylenchussp., rhizobacteria + organic carbon exhibited 51% and 45% mortality at higher and lower concentrations, respectively. Under greenhouse conditions, B.subtilis 20% + B. licheniformis 20% and rhizobacteria + organic carbonwere more effective in reducing nematode population densities,compared to the control.