Pests and Diseases 
Noni Stem Canker
A noni stem lesion (canker) at the interface between succulent
(green) and woody (brown) tissue leaves a gaping hole in the
bark. |
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Disease: Noni stem canker.
Pathogen: The cause noni stem canker is unknown,
although the disease is associated with an unidentified species
of fungus (an ascomycete).
Symptoms: Noni stem
canker is characterized by a progressive rot of stem at the
interface between woody and green stem tissues. Stem may be
girdled and collapse, leading to plant death. Stem lesions are
irregular in shape with roughened, dark borders and an overall
corky appearance.
Disease distribution: This
disease is limited to high-rainfall areas where noni is grown,
i.e., Puna district and Hilo/Panaewa on the island of Hawaii..
Impact: Some plants may recover from this disease
with proper management.
Epidemiology: Noni stem
canker is favored by warm, wet weather.
Control:
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- In nurseries, rogue or prune severely infected plants.
If pruning, sever the diseased stem at least 1 inch below
the stem canker.
- Humidity management through plant spacing and pruning,
weed control, good drainage, etc.
- Minimize stem wounding in nurseries.
- Protective or therapeutic applications of approved fungicides.
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| Notes: Noni stem canker
has not been previously reported to occur in Hawaii or elsewhere
in the world. |
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