Evaluation of fungicides as protective and curative treatments against canker disease of Eucalyptus urograndis in Sarawak, Malaysia
Plantations of the genus Eucalyptus L’Hér have rapidly expanded in Sarawak, Malaysia, accounting for 19% of the total forest plantation area. In a routine forest health surveillance conducted in 2022 at Sarawak, Malaysia, tree stands of the hybrid between Eucalyptus grandis x Eucalyptus urophylla...
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| Format: | Thesis |
| Language: | en |
| Published: |
2024
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/122503/1/122503.pdf http://psasir.upm.edu.my/id/eprint/122503/ https://ethesis.upm.edu.my/id/eprint/18592 |
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| Summary: | Plantations of the genus Eucalyptus L’Hér have rapidly expanded in Sarawak,
Malaysia, accounting for 19% of the total forest plantation area. In a routine
forest health surveillance conducted in 2022 at Sarawak, Malaysia, tree stands
of the hybrid between Eucalyptus grandis x Eucalyptus urophylla hybrid better
known as Eucalyptus urograndis were detected with symptoms of stem canker
disease caused by Chrysoporthe infection. Given the limited information on
the chemical control of Chrysoporthe stem canker disease, there is a growing
need to develop effective chemical control strategies to protect and cure
Chrysoporthe infection on E. urograndis trees. Therefore, this study aimed to
identify the causal pathogen of this stem canker disease in E. urograndis
stands in Sarawak, Malaysia, and evaluate the efficacy of various fungicides
as curative and protectant treatments on canker infection using artificial
inoculation methods. All isolates were first collected and subjected to
molecular identification and pathogenicity analysis. The inhabitation efficacy of five licensed fungicides: thiram, prochloraz manganese chloride, copper
hydroxide, dimethomorph, and mancozeb against the disease pathogen was
evaluated through an in vitro test. The performance of these fungicides was
then assessed through protective and curative field experiments on 10-yearold
E. urograndis trees using the artificial inoculation technique. The isolates
were identified as Chrysoporthe deuterocubensis based on morphology and
through comparisons of DNA sequence data from the ITS1/ITS4, β-tubulin 2
gene regions. Isolate CHRY18 recorded the highest virulence based on the
pathogenicity test. The in-vitro efficacy tests showed that prochloraz
manganese chloride achieved 100% inhibition against C. deuterocubensis at
1.0 mg/mL. Thiram significantly inhibited C. deuterocubensis infection in the
protective experiment, yielding the shortest lesion length (19.40 mm)
compared to the non-treated control (47.48 mm) at 20 weeks post-inoculation.
In the curative experiment, a reduction of 54.7% in lesion length was observed
in inoculated symptomatic trees after 20 weeks of post-fungicide treatment by
copper hydroxide. In conclusion, this study demonstrated that the combination
of prochloraz manganese chloride and copper hydroxide could be utilised an
as effective chemical control of C. deuterocubensis stem canker on E.
urograndis. |
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