How do I get rid of this weed in my buffalo lawn?When I dig it out it has a thick white root.

Thank you for contacting Yates.

Looks like the lawn is infested by Mullumbimby. Unfortunately we don't have a selective herbicide to control the weeds in lawn, you may try spot spray with Yates Zero Rapid 1-Hour Action Weedkiller which is a contact herbicide. Take care when applying as it will kill any plants it contacts. Click here for more info: https://www.yates.com.au/product/garden-weed-control/general-garden-weed-control/yates-zero-rapid-1-hr-action-weedkiller