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

Publication date: Available online 17 June 2019Source: Biological ControlAuthor(s): Juan M. Arjona-López, Sandra Tienda, Isabel Arjona-Girona, Francisco M. Cazorla, Carlos J. López-HerreraAbstractAvocado 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...

Source: Biological Control - June 18, 2019 Category: Biology Source Type: research