"Noxious weed" as defined in Wis. Stat. 66.0407 means "Canada thistle, leafy spurge and field bindweed" and any other weed the governing body or county determines by resolution or ordinance to be noxious within its boundaries. Landowners have an obligation to destroy noxious weeds, and municipalities have an obligation to destroy them on public lands and road right-of-ways. On or before May 15, towns can annually publish a class 2 notice stating that every landowner is required to destroy these weeds (note that this publication is not mandatory). If noxious weeds are not destroyed on private land, the town board does have the authority to take care of the problem after giving notice to the landowner; however, I would not recommend entering upon private land, even when you have the authority to do so, unless the landowner consented to this and is not objecting to this action. If you gave actual notice to the landowner and he still objects, it may be necessary to have a court order issued to protect the town and authorize a law enforcement officer to be present to enforce the court order.