Abstract:
This study was designed to evaluate the antagonistic effects of rhizobacterial
antagonists against Coffee Wilt Disease (CWD) caused by Gibberella xylarioides
underin vitro and in vivo conditions. Arabica coffee is Ethiopia’s
main export crop. However, the production and productivity of coffee is being
challenged primarily by coffee vascular disease (tracheomycosis).The greenhouse
antagonism study was conducted with four antagonistic bacteria of one Bacillus
(JU544) and three Pseudomonas spp. (JU941, JU13 and JU23). Out of 81
rhizobacterial antagonists tested on Half Strength King’s B (HSKB) medium
against G. xylarioides, 13.6% of them significantly (p<0.0001) reduced
the radial mycelial growth of the pathogen. From 11 rhizobacterial isolates
tested for their phytobeneficial traits, eight of them produced protease. Nevertheless,
five of them produced Hydrogen Cyanide (HCN) and other lytic enzymes. The bio-control
agents, time of applications and the interaction of the two were significantly
(p<0.0001) reduced the CWD severity and incidence under greenhouse conditions.
The CWD control efficiency was significant (p<0.0001) and the highest bio-control
efficiency was 72.64% when the coffee seedlings were treated with Bacillus
spp. (JU544) seven days before the pathogen. The bacterial antagonists, time
of applications and interaction of the two significantly (p<0.001) reduced
the progression of CWD incidence. The rhizobacterial antagonists especially
Bacillus spp. (JU544) effectively reduced CWD severity and incidence
under greenhouse condition and can be further evaluated under field condition
to ascertain their future applicability for inoculum development.
Melkamu Tiru, Diriba Muleta, Gezahegn Berecha and Girma Adugna, 2013. Antagonistic Effects of Rhizobacteria Against Coffee Wilt Disease Caused
by Gibberella xylarioides. Asian Journal of Plant Pathology, 7: 109-122.
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