Use this gridded observation board to track the number of mites in your hive. Can be cut to size with scissors or a paper cutter, but please measure carefully first.
Use vegetable oil, organic shortening, petroleum jelly, or cooking spray to make the surface sticky.
Place this under a screened bottom board for observation. Not UV-resistant so do not leave this in the sun.
Re-flatten between two outer covers. Do not fold as it will crease. Scrape off excess sugar/oil/debris with a plastic , drywall knife. Wash with soap and water.