Scientists have discovered the first nest of so-called murder hornets in the United States and plan to wipe it out Saturday to protect native honeybees, officials in Washington state said. After weeks of searching, the agency said it found the nest of Asian giant hornets in Blaine, a city north of Seattle near the Canadian border. The world’s largest hornet at 2 inches (5 centimeters) long, the invasive insects can decimate entire hives of honeybees and deliver painful stings to people.