Thousands of gardeners, wagons in tow, lined up at the State Fair grandstand this weekend for the Friends School plant sale as they jockeyed for position at the official start of Minnesota’s annual spring planting frenzy. They were also standing at the forefront of what has been a swift and surprisingly successful consumer revolt against a class of pesticides widely blamed for the decline in honeybees and other pollinators. Thanks to pressure from backyard gardeners…