In the cherry orchards of northwest Michigan around Traverse City, growers use a mixture of methods to control their archenemies: cherry fruit fly, plum curculio, and cherry leaf spot. Some growers use airblast sprayers while others use air-curtain sprayers. Some run their sprayers down the middle of every tree row (ERM) and apply spray to both sides of every tree, and some skip a row (alternate row middle, or ARM) and spray every other row, often tightening up intervals. All growers use the recommended rates of chemicals—so many ounces per hundred gallons of water, but those using ARM spray only […]