Fungal threat to eucalypt forests

The eucalypt forests and woodlands are at risk from an exotic disease - a rust fungus capable of attacking a broad range of our unique vegetation.

Scientists at CSIRO have mounted a three year program to reduce the risk of the rust Puccinia psidii, (guava rust), which damages eucalypts and related trees and shrubs in South and Central America, from reaching our shores.

According to Dr Inez Tommerup, the rust is a serious disease of young eucalypts, which attacks shoots of juvenile plants and can kill up to 90 per cent of seedlings. The rust has the potential to invade and damage ecosystems across the continent and, once established, there would be little to do to prevent it.

DNA fingerprinting tests capable of detecting and identifying the invader no matter which host plant was infected are being developed. The detection system will also be useful in screening importations of seed of eucalypts and related plants to assist quarantine measures to exclude this disease from our shores.

According to Dr Tommerup, resistant tree strains can be bred but this is only a solution for plantation forestry and bush replanting programs, not for native forests and national parks. Rust can be controlled by spraying fungicide, but this would be prohibitively costly across large areas, as well as undesirable from an environmental standpoint.

Item provided courtesy of The CSIRO