Introduction.

Mustard production (Brassica rapa sp. Pekinensis) is affected by the disease caused by Plasmodiophora brassicae.

Objective.

To determine the effect of Organic Matter, Mountain Microorganisms and Fertibiol, for the biological control of P. brassicae.

Materials and methods.

The designed treatments were evaluated individually and in combination, the variables evaluated were fresh and dry aerial and radical weight, root-stem ratio (R/T), radical severity index and spore persistence in the soil (rtPCR). Two culture cycles and 2 evaluations were performed. The Kruscal-Wallis, Shapiro-Wilks and Levene, ANDEVA tests and the DGC (Di Rienzo, Guzmán & Casanoves) test for the separation of means were used.

Results.

The treatments containing organic matter obtained the highest values for the variables of fresh weight and dry weight, both for the aerial part (more than 300% compared to the control) and the radical part. The R/T ratio was lower, and therefore more favorable, in the treatment with organic matter, with a value of 0.22. For the severity index, the MM treatment had the lowest value in the 2 evaluations, while the treatments with organic matter showed the highest value, but this did not affect the yield negatively. For the persistence variable, it was possible to determine that in the control treatment there was a decrease in the amount of germinating spores with the advance in time and that the treatments applied caused variable responses regarding this behavior, showing equations with different slopes and very different coefficients of variation. The treatment with MM presented for the second evaluation the lowest average amount of spores and the lowest radical severity index.

Conclusion.

The organic matter improved the yield of the plants and the use of MM reduced the severity and showed potential to reduce the presence of spores in the soil.