Background

Spinyhead sida

Spinyhead sida is a tough, fast-spreading invasive weed threatening the productivity and biodiversity of northern Australian rangelands. With its woody stems, deep taproots, and prolific seed production, it quickly outcompetes native and pasture species. Worse still, livestock avoid heavily infested areas, reducing grazing efficiency and land value.

Nature’s Ally: The Sida Leaf Beetle

Since 1989, the sida beetle, Calligrapha pantherina —imported from Mexico—has been quietly working to suppress spinyhead sida. These beetles feed voraciously on the weed, reducing its seed output and weakening its hold on the land. But there’s a catch: sida beetle populations fluctuate with the seasons, and sida often gets a head start during the wet season before beetles can catch up.

A New Approach: Community-Powered Biocontrol

We’re launching a community-focused project to rear beetles over the dry season and release them early giving them a head start and helping to reclaim rangelands. We’re inviting ranger groups, land managers, and community organisations to co-design and lead this two-year initiative. Together, we’ll answer key questions:

1. How can we build and manage local insectaries for sida beetle rearing?
2. Where and when should sida beetles be released for maximum impact?
3. How do we monitor and measure the success of sida beetle releases?

If interested in being involved

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