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For any introduction and expanded planting of a new plant
species or even a new cultivar, it is important that the introduction
is not an alternative host for any disease of economic importance
to major crops in the country. We, therefore pay special attention
to any pest and disease affecting Vetiver.
Results
In the period under observation, fungal attack was observed
and identified as:
- Nigrospora sp.
- Curvularia sp.
- Helminthosporium sp. (Photo 49)
With the help of a mycologist, we isolated the inoculum involved.
We then tried to inoculate new emergent leaves (Photo 50).
Our first two attempts failed to produce similar symptoms despite
using all known information available to us for such actions.
It was only recently (February 1991) at the third attempt using
cut leaves in inoculation chamber that we were able to inoculate
and develop symptoms using Helminthosporium sp. spores.
Nigrospora sp. and Curvularia sp. were only pathogenic
on detached leaves that had been subjected to wounding.
CONCLUSION
- Of the many areas planted only two sites experienced such
fungal attacks and these are in the crowded nurseries of RRIM
Experiment Station, Sungei Buloh.
- The plants in the affected plots were topped at 40 cm. Thereafter,
growth continued as normal.
- There are difficulties to inoculate with the isolated inoculum.
- All the above points suggest the fungal attacks to be non-virulent.
- However, on examining the checklist of hosts and pests in
Malaysia, we spot certain potential hosts of economic importance.
These are summarised below:
|
Pest |
Disease |
Host |
|
Curvularia lunata (Wakker) & Boedijn |
(leaf spot) |
Elaeis guineensis Jacq (oil palm) |
|
Curvularia maculans (Bancroft) Boedijn |
(leaf spot) |
Elaeis guineensis Jacq (oil palm) |
|
Helminthosporium halodes Petch. |
(leaf spot) |
Elaeis guineensis Jacq. (oil palm) |
|
Helminthosporium incurvatum Bernard |
(leaf spot) |
Cocos nucifera L. (coconut) |
|
Helminthosporium maydis Nelson |
|
Zea mays L. (maize) |
|
Helminthosporium rostratum Petch. |
(leaf spot) |
Elaeis guineensis Jacq. (oil palm) |
|
Helminthosporium (Drechslera) sacchari Link. |
(sugar cane eye spot) |
Saccharum officinarum L. (sugar cane) |
|
Helminthosporium sp. |
(leaf disease) |
Elaeis guineensis Jacq. (oil palm) |
Helminthosporium stenospilum (Drechsler)
Subram & Jain |
(brown stripe) |
Saccharum officinarum L. (sugar cane) |
|
Helminthosporium turcicum Pass. |
(leaf blight) |
Zea mays L. (maize) |
It is therefore important to identify the correct species and
cultivar of the various fungi attacking Vetiver albeit
on a small scale. Such knowledge in not available in Malaysia
and we therefore plan to send our inoculum to the British Mycology
Institute for identification.
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