Pink disease
Erythricium salmonicolor
List of symptoms/signs
Leaves - abnormal colours
Leaves - necrotic areas
Leaves - wilting
Stems - canker on woody stem
Stems - discoloration of bark
Stems - gummosis or resinosis
Stems - mould growth on lesion
Stems - mycelium present
Symptoms
Initial symptoms vary with the host. On Hevea, the initial stages of infection are seen as drops of latex and a silky-white mycelial growth on the surface of brown bark. In Piper, sterile pink/white pustules of around 1 mm diameter appear on the young green stems. In Citrus, the sterile pustules may appear first, sometimes with gummosis. In Theobroma, infection is usually first seen as a sparse white mycelium (web) on the bark surface. The surface mycelium is easily overlooked, particularly where the bark is wet.
The mycelium spreads mainly along the underside of the branch and sterile pink/white mycelial pustules appear through cracks in the bark and through the pores of the swollen lenticels, about 1-8 cm behind the leading edge of the infection. Hyphae penetrate the branch, causing progressive death of distal tissues. Leaves distal to the infection turn light green in the interveinal areas and then scorch brown from the margins. The affected leaves remain attached to the plant for a long time, giving an appearance similar to that of a broken branch.
The characteristic pink/white or pink/orange basidiomatal encrustation develops mostly towards the underside of the branch, although it can develop around the entire circumference of the stem; it can reach 2 m in length. The crust is initially smooth, but cracks and becomes paler as it ages. Conidia are sometimes produced, on orange/red pustules scattered over the bark surface. Long black streaks of coagulated latex or gums appear on infected branches of Hevea or Theobroma, and open wounds develop as the bark cankers and splits.
The fungus rarely causes death of mature trees, but can kill young trees.
Initial symptoms vary with the host. On Hevea, the initial stages of infection are seen as drops of latex and a silky-white mycelial growth on the surface of brown bark. In Piper, sterile pink/white pustules of around 1 mm diameter appear on the young green stems. In Citrus, the sterile pustules may appear first, sometimes with gummosis. In Theobroma, infection is usually first seen as a sparse white mycelium (web) on the bark surface. The surface mycelium is easily overlooked, particularly where the bark is wet.
The mycelium spreads mainly along the underside of the branch and sterile pink/white mycelial pustules appear through cracks in the bark and through the pores of the swollen lenticels, about 1-8 cm behind the leading edge of the infection. Hyphae penetrate the branch, causing progressive death of distal tissues. Leaves distal to the infection turn light green in the interveinal areas and then scorch brown from the margins. The affected leaves remain attached to the plant for a long time, giving an appearance similar to that of a broken branch.
The characteristic pink/white or pink/orange basidiomatal encrustation develops mostly towards the underside of the branch, although it can develop around the entire circumference of the stem; it can reach 2 m in length. The crust is initially smooth, but cracks and becomes paler as it ages. Conidia are sometimes produced, on orange/red pustules scattered over the bark surface. Long black streaks of coagulated latex or gums appear on infected branches of Hevea or Theobroma, and open wounds develop as the bark cankers and splits.
The fungus rarely causes death of mature trees, but can kill young trees.
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