Abstract:
Trichoderma spp. have long
been used as biological control agents
against plant fungal diseases, but the
mechanisms by which the fungi confer
protection are not well understood. Our goal
in this study was to isolate species of
Trichoderma, that exhibit high levels of
biocontrol efficacy from natural
environments and to investigate the
mechanisms by which these strains confer
plant protection. In this study, efficacy of
the native isolates of Trichoderma species to
promote the growth and yield parameters of
tomato and to manage Fusarium wilt
disease under in vitro and in vivo conditions
were investigated. The dominant pathogen,
which causes Fusarium wilt of tomato, was
isolated and identified as Fusarium
oxysporum f. sp. lycopersici (FOL). Twenty
eight native Trichoderma antagonists were
isolated from healthy tomato rhizosphere
soil in different geographical regions of
Mazandaran province, Iran. Under in vitro
conditions, the results revealed that
Trichoderma harzianum, isolate N-8, was
found to inhibit effectively the radial
mycelial growth of the pathogen (by
68.22%). Under greenhouse conditions, the
application of T. harzianum (N-8) exhibited
the least disease incidence (by 14.75%).
Also, tomato plants treated with T.
harzianum (N-8) isolate showed a
significant stimulatory effect on plant height
(by 70.13 cm) and the dry weight (by
265.42 g) of tomato plants, in comparison to
untreated control (54.6 cm and 195.5 g).
Therefore, the antagonist T. harzianum
(N-8) is chosen to be the most promising
bio-control agent for F. oxysporum f. sp.
lycopersici. On the base of present study,
the biocontrol agents of plant diseases might
be exploited for sustainable disease
management programs to save
environmental risk.
