Trials against gazania: farmers combat the weed

The gazania plant is spreading from gardens, posing a threat to valuable agricultural land and natural ecosystems, including species of high conservation value. The Grains Research and Development Corporation (GRDC) has directed $700,000 toward a three-year project aimed at combating this weed. Preliminary work has shown the plant to be widespread in South Australia and parts of Western Australia.

Dr Bajwa reported that the highest effectiveness was shown by a combination of mechanical tillage (deep loosening to remove weeds) and herbicide spraying, with some farmers employing computer vision technologies. Despite erosion risks and the undesirability of tillage for certain soil types, a strategic one-off application of this method can be effective. Currently, there are no registered products against gazanias, and farmers use herbicide mixtures; however, over the next year or two, researchers expect to obtain permits for the use or registration of new products.

Loxton farmer Paul Rudiger has faced a situation where, due to gazanias, some of his fields have become unsuitable for growing grain crops, as the powerful root system of the weeds takes up all soil moisture. Intensive and costly cultivation allows him to hold the weed in check to preserve his crops. Another local farmer, Paul Kaesler, also employs spraying and tillage on his family farm. He expressed concern that the approval process for new herbicides is moving too slowly, and emphasized the importance of the public complying with bans on the sale and movement of gazanias in South Australia.