A litter of week-old golden retrievers look more like big hamsters than canines. But these nine tiny balls of fur are a big source of hope for Napa Valley growers whose vineyards are blighted by infestations of vine mealybug.

For the past three years, the near-invisible pest has vexed growers as it clings to vines, sapping their energy, inviting molds and viruses and ruining grape crops. If left unchecked, mealybugs can kill a vine within five years. Currently there are 36 mealybug infestations in Napa County, according to the Napa County Agricultural Commissioner's Office.

Meanwhile, before the litter of newborn pups fully open their eyes they will be introduced to what might become the most meaningful smell of their lives: the pheromone emitted by the female vine mealybug to attract her male counterpart.

Eventually the puppies will be trained to identify the scent, to search vineyards for the pheromone and alert humans to exactly where the 1/8-inch-long arthropods have burrowed on a vine.

Dr. Bonnie Bergin, who is leading the research project, explained that a dog's sense of smell is thousands to a million times stronger than a human's.

"A third of their brain is dedicated to their olfactory system (sense of smell), compared to ours, which is hardly anything," Bergin said. "Our world is colored by our visual senses and their world is colored by odor."

The first and most crucial breakthrough of the project came when researchers found dogs could indeed detect the female bug's pheromone. Since then, grape growers have contributed about $30,000 to fund the first year of what's anticipated to be a two-year sniffer-dog research project led by Bergin's Assistance Dog Institute in Santa Rosa. Fundraising for the project's second year is already underway.

The latest litter of pups is the first generation specially bred for the high-energy traits that make good scent detection dogs. The father of the litter is the uncle of America's second-best search and rescue dog, a 3-year-old golden retriever named Kane who works for the Federal Emergency Management Agency. The mother is a high-energy service dog from the Assistance Dog Institute.

As the puppies take their first steps and take in their first scents, the stakes of the sniffer-dog research project increase. The vine mealybug continues to reach new corners of Napa County. Efforts to eradicate the bug -- labor costs, pesticides, extra sanitation measures -- typically raise the cost of growing grapes by at least $1,000 an acre annually.

The hope is that the dogs can do what humans so far haven't been able to: catch the critters before their populations explode and they become obvious to the naked eye. By that time, the mealybugs usually have a stranglehold on a vine -- reducing its growth and yields and leaving sticky trails of honeydew extract everywhere.

Meanwhile Joy, a boisterous 8-month-old golden retriever pup from the Assistance Dog Institute, is becoming the poster-dog for early detection.

On Friday she won the admiration of about two dozen growers attending a mealybug workshop hosted by the Napa Valley Grape Growers.

Joy sniffed out an entire dining room, packed with growers and strange vineyard smells, to find the mealybug pheromone pellet her handler had hidden. Joy alerted her handler, Judy Fridono, with a few piercing barks.

Joy's pheromone-smelling expertise is the result of a structured training process that started by introducing the scent to Joy a few weeks after her birth, just as the pup entered consciousness. Bergin explained the idea is to imprint the smell in the dog's brain at a very young age so it instinctively grasps "this scent is very important in my life and I have to do something about it."

As Joy matured from a cuddly newborn into a puppy, she was trained to identify the smell and alert her handler every time she did so by barking. These days, Joy scours her surroundings for the smell upon hearing the command "Search!"

The next challenge will be teaching Joy to search for the pheromone scent in a vineyard, despite distractions such as rabbits and competing smells, like freshly mown grass and pesticides.

Bergin expressed confidence at the Napa Valley Grape Growers meeting Friday that the dogs can take on this added responsibility if paired with the right dog handler, which she also described as the sniffer dog's "life partner."

"Dogs work for people they love. The more they take the dog with them and the closer the dog is to them the more the dog wants to work for them," Bergin said. "Because of the relationship and bonding that's required I don't think the dog can belong to a company that says, 'OK, John now you take Fido today.' If the handler's not committed to having the dog with them at all times the dog may start thinking, 'I kinda like you, and I'll search for a while, but that rabbit over there looks more exciting.'"