LACROSSE, Wis. – The Mayo Clinic opened a stand-alone Covid testing site at 10th and Market streets, just south of downtown. Benjamin G. Anderson, a nurse administrator at Mayo in La Crosse, noted growing concern about the virulent Delta mutation. The site, he said, is convenient for many people. Appointments necessary: 507-293-9525. Meanwhile, Anderson said, testing also is available at other Mayo sites.