Control of avocado white root rot using non-pathogenic Rosellinia necatrix isolates combined with low concentration of fluazinam

Different studies to control the Rosellinia necatrix growth in vitro and avocado white root rot in vivo were performed, using two non-pathogenic R. necatrix isolates (Rn12 and Rn29) combined with fluazinam. The application of non-pathogenic isolates alone showed significant growth reduction as compared to R. necatrix pathogenic isolates in a PDA growth medium. The combination of both non-pathogenic isolates plus fluazinam at 0.01 mg l−1 significantly increased the reduction of the pathogen growth in vitro. Additionally, the combination of the lowest fluazinam concentration (0.001%) plus Rn12 improved control of the disease as compared when either the same fungicide rate was used alone or this isolate was applied alone on plants, showing a similar response to the use of the highest concentration of fluazinam applied alone (0.01%). In this work, we have obtained a new, integrated biological control method against this avocado disease using non-pathogenic R. necatrix isolates combined with low doses of fluazinam.
This study was supported partly by the Plan Nacional I + D + I Ministerio de Economía y Competitividad (AGL 2014–52518-C2-2-R), Spain. In addition, the research was co-financed by FEDER funds (EU).