Biocontrole da ferrugem asiática e da podridão vermelha da raiz, em soja, utilizando diferentes tratamentos biológicos nas sementes

Abstract

Soya (Glycine max) is the main oil crop grown in the world, and Brazil ranks second among the producing countries. However many factors affect the achievement of even more significant gains with the crop, where diseases occupy a prominent position, especially Asian soybean rust (Phakopsora pachyrhizi) and red root rot (Fusarium solani). Thus high loads of fungicides are applied to minimize losses, however, results associated with the use of biological control of these diseases may be promising. The objective of this work was to verify the potential of control of Asian rust and red root rot in soybean plants, whose seeds were submitted to different biological treatments based on Trichoderma asperellum, Bacillus spp. and Azospirillum brasilense, alone or in admixture. For this purpose, soybean seeds of the cultivar BMX Magna RR were submitted to the following biological treatments T1: Azospirillum brasilense (SimbioseMaíz®) at the dose of 4000 ml per 100 kg of seeds; T2: Trichoderma asperellum (Quality® WG) at the dose of 200g per 100 kg of seeds; T3: Bacillus spp. (selected by Rohrig (2016)) at the concentration of 1.5x109 colony forming units (CFU) per mL; T4: A. brasilense + Bacillus spp .; T5: T. asperellum + Bacillus spp; T6: A. brasilense + T. asperellum. In addition, a control treatment (T7) was used, where the seeds received no treatment. The design was completely randomized (DIC) with 7 treatments and 4 replicates. Evaluations were made regarding the severity of the diseases as well as measurements on the aerial part and the radicular of the plants. It was observed that the microorganisms in the mixture were more efficient, both in the control and in the promotion of growth, for both fungi, in the majority of the evaluated variables. Further studies with the most efficient treatments are necessary, in order to verify the control stability of these microorganisms.