ORIGINAL RESEARCH
The Efficacy of Various Bacterial Organisms
for Biocontrol of Fusarium Root Rot
of Olive in Tunisia
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1
Arid Lands and Oases Cropping Laboratory, The Arid Regions Institute of Medenine, Tunisia
2
Regional Research Center in Oasis Agriculture of Degache, Tozeur, Tunisia
3
Rural Laboratory, National Institute of Agronomic of Tunisia
Submission date: 2017-12-08
Final revision date: 2018-04-11
Acceptance date: 2018-04-16
Online publication date: 2019-09-09
Publication date: 2019-10-23
Corresponding author
Amira Bouzoumita
Arid Regions Institute of Medenine, Tunisia, Medenine, Tunisia, 4119 Medenine,, Tunisia
Pol. J. Environ. Stud. 2020;29(1):11-16
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ABSTRACT
Biocontrol research has the potential for managing Fusarium root rot of olive. This latter is treated
by the use of isolated bacteria from the soil of olive orchards of Tunisia: Bacillus Licheniformis
and Enterobacter Colcae. It was demonstrated that these two bacteria are effective against Fusarium
solani and oxysporum. In an initial screening, two efficacy bacteria were isolated with a reduction
of disease incidence. In vitro, both biocontrol agents were highly tolerant to the carbendazime
fungicide commonly used to control Fusarium diseases. It was observed that carbendazime reduced
disease symptoms at a concentration of >50 μg mL−1. The combination of the bacterial isolates
and carbendazime gave a significant (P≤0, 05) control of the disease when plants were artificially
inoculated with the pathogen. The application of carbendazime at a low concentration (10 μg mL−1)
in combination with Bacillus B4 reduced disease symptoms by 51%, compared with a reduction
of 46% obtained with the bacterium alone and no control with the chemical treatment alone.
A combination of Bacillus with fungicide increased the application rate of 10 μg mL−1 carbendazime
and significantly reduced disease symptoms by 74% compared to 34% with carbendazime treatment
alone and, respectively, a combination fungicide and Enterobacter E4 increased the disease by 84%
compared with 55% for bacteria alone. In this experiment, the integrated treatment also slightly
outperformed the application of 100 μg mL−1 bacteria Bacillus and Enterobcater applied, and without
fungicide also provided good disease control.