Introduction: During the past three years many white mangrove trees (Avicennia marina [Forsk.] Vierh.) have died in the Gladstone area of central coastal Queensland. A few dead trees were first observed in 1978 in the vicinity of the Gladstone power house by Dr. Peter Saenger, a biological consultant with the Queensland Electricity Generating Board. The number of deaths increased considerably in 1979 and at present approximately 70 per cent of white mangrove trees growing near the mouths of the Calliope River and Auckland Creek have died (Figure 1). Twelve species of mangrove occur in the Gladstone area (Saenger and Robson, 1977), but only Avciennia marina is affected.
The first visible symptom in the aerial parts of affected trees is a wilting of the leaves. These leaves then become yellow and gradually fall so that trees are almost completely defoliated. The lateral absorbing rootlets which are borne at base of the pneumotophores become black and decayed. A truck rot is also occasionally present. This originates at ground level and may extend two metres up the trunk. Trunk lesions are a deep purple colour, and when this discoloured tissue is cut it has a sweet, sickly odour.
How to Cite:
Pegg, K.G. and Foresberg, L.I., 2010. Phytophthora in Queensland mangroves. Wetlands Australia, 1(1), pp.2–3. DOI: http://doi.org/10.31646/wa.44