Norb Gernes, left, Eden Prairie’s oldest residential beekeeper, is passing the beekeeping torch to his nephew, Sam Kryzer. (Renee Rushdy) For more than 50 years, during pleasant spring and summer days in northwest Eden Prairie, Norb Gernes could often be found doing what he loved to do: lingering near the hum of his backyard hives, watching honeybees lift off and return as if they were clocking in for a shift. With increasing age and declining h…