What spray can I use on a couch grass to kill paspalum? Weed n Feed does not work.

Unfortunately, we don't have a selective herbicide for grassy weeds in lawn as Weed n feed is only registered for broadleaf weeds, 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