Frank Gouin is giving up on growing peaches after invasive stink bugs wiped out 60 percent of his crop this year. (Adrian Higgins/The Washington Post)

Peach trees look as if they are wilting. Get beyond the flagging leaves and you see that the trees in Frank Gouin’s orchard are robust, mature and free of the leaf spots, oozing gum and mummified fruit that afflict neglected peaches.

Gouin has spent 20 years raising the perfect peach, starting by sowing the rootstock from seed and, a year later, grafting a bud of the desired variety on to the seedling. From a pointed bud the size of a grain of rice, each tree has grown six feet wide and 10 feet high and produced countless bushels of luscious fruit in the summers since.

Gouin, with his Captain Ahab beard and piercing blue eyes, looks like the elder of a 19th-century sect, but he is in reality a guy who has devoted his life to raising plants and teaching others how to do it. The pesticides and practices have changed since he got into horticulture in the 1950s, but there was an abiding belief that there was no pest that could not be beaten or managed. When it comes to peaches, Gouin this summer saw that faith shattered. He has harvested his last Prunus persica.

He will continue raising Christmas trees and persimmons, but the loss of the peach marks to a large degree the end of a journey that began by fluke.

His life with plants wasn’t meant to be. When he was a boy in central New Hampshire, he contracted scarlet fever followed by rheumatic fever. He was in bed for a year. One day, the doctor took his mother aside and told her: “Your son won’t live to get a driver’s license.”

Brown marmorated stink bug (Halyomorpha halys) . (bigstockphoto/BIGSTOCKPHOTO)

Forbidden to play sports, 9-year-old Frank was instructed by his father to look after the vegetable patch. This is where he caught another fever — for gardening. He put himself through horticulture school by managing a large blueberry and apple orchard. He gravitated to the University of Maryland for advanced degrees, joined the faculty, and over the years became an expert in feeding and protecting nursery stock, on the seasonal effects of Roundup and the science of composting. Along the way, he forgot to die. He has had 73 birthdays and counting.

Timing is as important to a fruit grower as it is to a stand-up comedian. In his one-acre, creekside orchard near Deale in Anne Arundel County, he sprays every 10 to 14 days to keep back an army of pests and diseases that want his peaches. They include two species of borer, various weevils and fungal organisms. The fruit must be thinned so the tree puts its energy into fewer, larger peaches. “People want a 21 / 2 to three-inch peach,” he said. “You can’t give away a two-inch peach.”

Thinning begins in April when the flowers are still in bud. Gouin ties a toilet brush to a stick and uses it to rub out half the blossoms. In late spring, he spends many days hand thinning the young, green fruit before it can get bigger than a golf ball.

Four years ago, Gouin noticed a stink bug on his fruit. Not to worry, he thought, the native brown stink bug is an occasional and minor pest of fruit. Except this one seemed smaller, and when you looked closely you could see that the margins of its shield-like carapace had white highlights.

Gouin and his fellow gardeners and orchardists know now that they were seeing the arrival of one of the most serious imported pests in American history. In early fall, the brown marmorated stink bug amasses in such numbers that homeowners are driven off their patios and porches, then the bug does its best to invade the house proper.

For growers of fruits and vegetables, the nightmare is all season long. The bug is thought to have stowed its way to eastern Pennsylvania from Asia in the mid-1990s. With no natural predators and several generations a year, its populations have exploded. Unlike the native stink bug, the nymphs as well as the adults feed on crops. Their tastes are wide and lavish, and include beans, sweet corn, tomatoes, apples, pears and, of course, peaches. They pierce the fruit to feed, injuring it.

Two years ago, Gouin lost about 2 percent of his crop to the stinkers. Last year, it was close to 10 percent. This year, it was 60 percent. Of his nectarines, essentially naked peaches, “I don’t think I picked five bushels out of 15 trees.”

The experts are recommending that farmers spray pesticides every five days to beat back the bug from hell. For Gouin, that would mean donning his air-filtered helmet and vinyl suit too often in the heat of a Chesapeake summer. Scientists are working hard to find a natural predator for the bug, but for Gouin, time has run out. After a lifetime of dealing with and beating pests, he is calling it quits. This winter, he will take a chainsaw to his 128 peach trees.

Sitting in the sun room of his ranch house, Gouin’s eyes keep shifting to see the bugs landing on the glass outside. After the feast, they want shelter. The brown marmorated stink bug — marmorated means marbled — has a primal form that some people might find beautiful, but Gouin sees the insect as grotesque. “I take great satisfaction in killing them.”