Bacillus methylotrophicus (LBCC0786) e Streptomyces griseovirides (LBCC0431) NO CONTROLE DE Pratylenchus brachyurus e Macrophomina phaseolina NA CULTURA DA SOJA

Abstract

Soybean (Glycine max) has a prominent role in the world economy with fundamental importance in human and animal nutrition. The root lesion nematode, Pratylenchus brachyurus, has caused significant economic losses to soybeans, mainly in the Midwest region of the country, with productivity losses of up to 50% of the crop. Gray root rot or charcoal rot, caused by the fungus Macrophomina phaseolina, is a root disease that is widespread in all growing regions, negatively interfering with soybean productivity. To live with this complex of diseases, biological control has been highlighted by the use of antagonistic microorganisms in order to reduce economic losses. This work aimed to verify the interaction and efficacy of Bacillus methylotrophicus (Onix®) and Streptomyces griseovirides (Lalstop K61) in the management of P. brachyurus in association with M. phaseolina in soybean. Laboratory experiments were carried out to verify the compatibility between S. griseovirides and B. methylotrophicus. The microorganisms were submitted to simultaneous exposure in Petri dishes and no growth inhibition was observed between them. A greenhouse experiment was installed to verify the development of soybean plants using the microorganisms separately and in combination, which showed no negative interference with the associated use of the products. In addition to the others, tests were carried out in a greenhouse to verify the effectiveness of the products in the management of P. brachyurus and M. phaseolina in isolation and in association. The severity of the disease in association with the nematode was lower when the biocontrol agents were used together compared to the control. The treatment with S. griseovirides showed higher fresh mass of shoots when both pathogens were inoculated. The use of S. griseovirides and B. methylotrophicus in association promoted an increase in plant height even in the presence of both pathogens. The use of biocontrol agents promoted the reduction of the population of P. brachyurus.