Bactérias de diferentes nichos no controle do complexo Fusarium spp x Meloidogyne e na produtividade da bananeira

Abstract

Aiming to study the bioaumentation of antagonists in the banana rhizosphere as a management strategy of the Fusarium x nematoid complex, three experiments were carried out. In the 1º experiment, inoculation times of bacteria were evaluated in the control of F. oxysporum f. sp. cubense and M. javanica on micropropagated seedlings of ‘Prata-Anã’ banana tree. The experiment was conducted in a greenhouse under a 2 x 12 + 3 factorial scheme, being: two application times of the biocontrol agents during the acclimatization period (Season 1) and after planting in pots (Season 2); 12 bacterial isolates; and three additional treatments: 1) inoculated seedlings with foc; 2) seedlings inoculated with foc + commercial biological product based on Trichoderma asperellum and 3) absolute control without inoculation of pathogen and bacterial agents. For the control trial of M. javanica the additional treatments consisted of: 1) seedlings inoculated with M. javanica; 2) inoculated seedlings M. javanica + commercial biological product based on Bacillus metlylotrophicus) and 3) absolute control without inoculation of pathogen and bacterial isolates. In the 2º. experiment, the reaction of the varieties ‘Prata-Anã and Maçã’ was evaluated to the nematode M. javanica (Mj) and the fungus F. oxysporum f. sp. cubense (foc), and the interactions between them and the effect of Bacillus sp on nematode reproduction and on the severity of Fusarium wilt. The experiment was conducted in a completely randomized design with seven replications in a 2 x 7 factorial scheme: two varieties of ‘Prata-Anã and Maçã’ banana, and seven treatments: 1) Absolute Witness (without pathogen and biocontrol agent); 2) seedlings inoculated with foc and nematoid plus the biocontrol agent (Bacillus sp. E-09); 3) seedlings inoculated with foc and nematoid without the biocontrol agent; 4) seed inoculated with foc and the biocontrol agent (Bacillus sp. E-09); 5) seedlings inoculated with foc without the biocontrol agent; 6) seedlings inoculated with Mj and the biocontrol agent (Bacillus sp. E-09); 7) seedlings inoculated with Mj without the biocontrol agent. In the 3º experiment, the formulation of Bacillus sp. in rice, as an inoculant in banana cultivation aimed at promoting growth. The experiment was carried out in a commercial banana growing area, in the city of Nova Porteirinha - MG, from September 2017 to December 2018. The experimental design was a randomized block design in a 2 x 4 factorial scheme, treatments consisted of two banana varieties Maçã and Prata-Anã and application of three formulations with species of microorganisms and the absolute control. The application times of the bacterial isolates interfere in the control of the wilt of Fusarium and M. javanica in micropropagated banana seedlings ‘Prata-Anã’. The isolates B. subtilis (R-34), Bacillus sp. (R-76), Bacillus sp. (E-07), B. pumilus (E-09) and Bacillus sp. (R-34), B. subtilis (R-42), Bacillus sp. (E-13) is a severity of the Fusarium wilt when submitted to the planting of ‘Prata-Anã’ banana seedlings. The isolates B. subtilis (R-34), B. subtilis (R-42), Bacillus sp (R-76) and B. pumilus (E-09) a reproductive capacity of M. javanica, when inoculated in aclimatization and after the planting of ‘Prata Anã’ banana seedlings in pots (Experiment 1). The simultaneous presence of M. javanica and foc without the inoculation of Bacillus sp. increases nematode reproduction and the severity of Fusarium wilt. The presence of Bacillus sp. reduces nematode reproduction and Fusarium wilt severity. The isolate Bacillus sp. Epi 09 presents potential for the treatment of banana tree seedlings for control of M. javanica and Fusarium wilt (Experiment 2). The number of fruits per shoot, shoot mass, shoot mass, shoot mass and diameter of the banana fruit were significantly influenced by the use of biological products, especially those containing Bacillus spp. Under field conditions tested Bacillus sp. (E-09) is maintained up to 180 days in the formulation based on rice and increases number of fruits per penca, mass of the bunch and the diameter of the fruit in banana tree; T. asperellum increases productivity of ‘Maçã’ banana tree (Experiment 3).