Potencial de controle do crestamento bacteriano comum do feijão com rizobactérias em pulverização foliar.

Abstract

Isolates bacterial biocontrollers of bacterial blight (BB) in common beans, through the seed microbiolization are known. However, there is no knowledge of the behavior of these isolates applied in leaves. In this context, the aims this study were: i) evaluate the potential BB control by foliar spray biocontrollers bacteria; ii) evaluate the effect of spray these bacteria when applied before and after the pathogen inoculation; iii) identify the potential of isolates biocontrollers bacteria to induce resistance in common bean plants to BB. To this, there were three essay in the greenhouse. In the essay I were realized spraying with bacterial suspensions with isolates: DFs93, DFs513, DFs769; and two combinations CO1 (DFs93 / DFs769 / DFs831) and CO3 (DFs348 / DFs769 / DFs831) in different moments of application: 48 and 24 hours before inoculation of pathogen (BIP) (Xanthomonas axonopodispv phaseoli- XAP) and 24 and 48 hours after inoculation of pathogen (API). In essay II were sprayed the isolates DFs513, DFs769 and CO3 combination, in 72 and 48 hours BPI and 48 hours API. Finally, essay III evaluated the potential of inducing resistance to CBB, through the spatial separation between pathogen and biocontroller. In the essay III, the isolates DFs513, DFs769 and CO3 combination, were sprayed 72 and 48 hours BPI. The spraying was carried out in different leaflets those where the pathogen was inoculated in two schemes: biocontroller in side leaflets and XAP in the apical leaflet; biocontroller in apical leaflet and XAP in the side leaflets. For all assays were realized five assessments of incidence, severity, calculated the área under the incidence progress curve (AUIPC) and area under the severity progress curve (AUSPC). In general, DFs769 and CO3 reduced the severity, AUIPC and AUDPC when applied preventively. The isolate DFs769 reduced the severity, AUIPC and AUDPC even when applied in different leaflet of pathogen aplication. The treatments DFs769 and CO3 are potential biocontroller of bacterial blight in common bean when applied by preventive foliar spray. Additionally, DFs769 treatment is a induction systemic resistance elicitor, and this is mechanism action this biocontroller, responsible for reducing the BB in common bean.