Defoliation, drooping and yellowing of noni leaves associated
with stem blight disease.
Yellowing and drooping of noni leaves associated with stem blight
Rotten roots and blackened basal stem associated with stem blight
disease. A white tuft of fungal mycelium (the fungus, Sclerotium
rolfsii) forms just above the soil line.
| Disease: Noni
Pathogen: Pathogens associated
with this disease are a fungus Sclerotium rolfsii, and
root-knot nematodes. Apparently, the disease occurs when plants
are greatly stressed from nematode attack and/or flooding.
Symptoms: Foliar chlorosis and wilting; stem girdling
at or near soil line; internal stem necrosis; stem rot; defoliation;
Signs: White fluffy fungal mycelium;
brown sclerotia at soil line.
The fungus associated with noni stem blight has a world wide
distribution, although the disease has only been observed in
the Puna district on the island of Hawaii.
Noni stem blight is an opportunistic disease favored by predisposing
stresses (flooding, poor drainage, wounding of stems, infection
by root knot nematodes).
- Avoid planting in low-lying areas with poor drainage.
- Avoid plant-parasitic nematodes.
- Avoid injuring stems with weed-whackers.
- Do not pile rocks around the base of noni plants, as they
may injure the stem.
- Avoid undue plant stresses.
Noni stem blight has not been reported previously to occur in
Hawaii or elsewhere in the world.