Combination of low concentrations of fluazinam and antagonistic rhizobacteria to control avocado white root rot

Avocado white root rot is a disease caused by the soil-borne pathogenic ascomycete Rosellinia necatrix Prill. In this work, we have carried out different experiments combining the contact fungicide fluazinam with biocontrol rhizobacterial strains of Pseudomonas chlororaphis and Bacillus subtilis, in order to reduce in vitro growth inhibition of R. necatrix and to control the disease in avocado plants. When combining fluazinam at a low concentration (0.01 mg L−1) with individual biocontrol bacterial strains, a slight reduction in fungal growth was observed (10 mm2 for PCL1606; 19 mm2 for PCL1601 and 11 mm2 for PCL1608) when compared with the use of the fungicide alone (31 mm2). From all the assayed rhizobacteria, the combined use of the rhizobacterial strain Pseudomonas chlororaphis PCL1606 with fluazinam showed the best fungal inhibition in in vitro tests (22–66%). The protective effect against avocado root rot in avocado plants was recorded using a concentration of fluazinam of 0.01%, but its effect was not improved when combined this fungicide with the biocontrol rhizobacteria PCL1606. However, when a lower concentration of fluazinam was tested (0.001%), the combination with PCL1601 or PCL1606 strains resulted in improved control of the disease than when using the fungicide alone with a reduction of 15% and 8% respectively. These results point to the development of an integrated tool to control avocado white root rot by using lower concentrations of fungicide, combined with a suitable biocontrol rhizobacteria, thus obtaining the protective effect on the plant, but reducing the chemical residues and preventing the development of fungal resistance.

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Bibliographic Details
Main Authors: Arjona-López, J. M., Tienda, Sandra, Arjona Girona, Isabel, Cazorla, Francisco Manuel, López Herrera, Carlos
Other Authors: Ministerio de Economía y Competitividad (España)
Format: artículo biblioteca
Language:English
Published: Elsevier 2019-09
Subjects:Bacillus spp., Fluazinam, Persea americana, Pseudomonas spp., Rhizobacteria, Rosellinia necatrix, White root rot,
Online Access:http://hdl.handle.net/10261/206706
http://dx.doi.org/10.13039/501100003329
http://dx.doi.org/10.13039/501100000780
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