Boosting willow control in south-east Australia

New research from CSIRO Plant Industry and the Centre for Plant Biodiversity Research could lead to more effective control strategies for one of Australia's biggest weed pests.

Willows are one of Australia's worst weeds. Since their introduction they have invaded rural water ways in Australia, where they impact on the health of water systems and force out native species. Controlling willows costs between $6 and $10 million every year, mainly in south-east Australia.

Willows spread in two ways - vegetative reproduction, when fragments break off trees and sprout roots, and by seed.

Vegetative reproduction can be managed within catchments, but seeding willows, like Pussy Willow, have the potential to move across catchments. Landcare managers want to know how far seeding willows can spread so they can effectively manage the problem.

In a recent pilot study, Dr Curt Brubaker, Dr Andrew Young and their team used DNA markers to investigate the way willows move across the Australian landscape.

A genetic analysis of Pussy Willow seedlings from the Dargo River and four nearby catchments in Gippsland, Victoria suggested that seed and pollen are moving across catchments. The preliminary conclusion is that seeding willows should be managed on a regional scale.

The next phase of the project aims to determine the relative frequencies of seed and pollen movement across catchments. This information will help accurately develop new management protocols.

The ultimate goal of this research is to use an improved understanding of willows' reproductive cycle to identify the most effective methods for controlling them in Australian riparian systems.

The Centre for Plant Biodiversity Research is a joint venture between CSIRO Plant Industry and the Department of the Environment and Heritage.

This work was carried out in collaboration with the Victorian East Gippsland and North East Catchment Management Authorities.

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