Trichoderma pers. ex fr. and its efficacy as a biological control agent of basal stem rot of oil palm (Elaeis guineensis jacq.)
This study evaluated the potential of species of Trichoderma as a bio-control agent against Ganoderma boninense Pat., the causal pathogen of 'basal stem rot' of oil palms. Out of 102 Trichoderma colony-forming units (CFU) isolated from oil palm rhizospheres, 39 were T. harzianum Rifai,...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2000
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/9095/1/FSAS_2000_23%20IR.pdf |
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| Summary: | This study evaluated the potential of species of Trichoderma as a bio-control agent
against Ganoderma boninense Pat., the causal pathogen of 'basal stem rot' of oil
palms. Out of 102 Trichoderma colony-forming units (CFU) isolated from oil palm
rhizospheres, 39 were T. harzianum Rifai, 38 were T. aureoviride Rifai, 19 were T.
longibrachiatum Rifai and 5 were T. virens (Miller, Giddens and A. A. Foster) von
Arx. Isolate T43 showed overlapping characteristics between T. hamatum and T.
harzianum and was termed 'indeterminable' taxonomically. All isolates were screened
for their antagonistic properties against G. boninense (isolate PP28) by dual culture
studies, from which isolates T32 (T. harzianum) and T128 (T. virens) were selected as
the two most effective antagonists. In vitro non-mycelial studies by normal and bilayer
poison agar techniques and of culture filtrates, showed that secondary metabolites
produced by the two selected isolates were able to suppress growth of Ganoderma on
agar as well. In greenhouse trials using Trichoderma-incorporated mulch, all 5 control plants were
killed by Ganoderma at 24 weeks after infection, whereas the survival rates were 60%
and 20% when treated with T32 and T128 respectively. These were 80% for T32 and
40% for T128 using clonal plants for the same experiment. Two out of 4 modes
showed very good disease control when Trichoderma was used as conidial suspension.
As a root coating supplemented by Trichoderma-incorporated mulch at the start of
experiment, the survival rate was 90% when treated with T32 and 70% with T128.
When applied directly (1 L/plant once every fortnight for 12 weeks), a survival rate of
90% using T32 and 80% using T128 were obtained. In the use of its secondary
metabolites, 2 out of 3 modes of application gave very good results. The first was by
direct application of secondary metabolites (300 ml/plant at fortnightly intervals for 6
times), which resulted in a survival rate of 70% when treated with T32 and 60% when
treated with T128. The second was its application as root coating followed by a single
boost of 300 ml of the metabolite given only once at the start of the experiment, which
resulted in a survival rate of 70% using T32 and 40% using T128.
Trichoderma treatments were found to be effective when applied at the start of
experiment but were no longer effective in delayed treatments of 6 to 8 weeks after
infection. T32 (T. harzianum) showed better efficacy than T128 (T. virens) for all
experiments. Trichoderma treatments which gave good survival rates and which could
be commercially exploited were its use in the form of conidial suspension, whether
applied indirectly as a root coating or poured directly on to soils of infected plants. |
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