A snail as big as your foot, an insect the size of chocolate sprinkles and a mold related to the one that caused the Irish potato famine are on the U.S. Department of Agriculture's list of the top pests that threaten America's crops and forestland.
The list comes out Monday.
Some of the 15 are new, some we've been fighting for decades. To attack them, "a sea change" in how we interact with our environment is starting to take place, says Scott Pfister, who directs the pest management department at the USDA's plant protection and quarantine division in College Park, Md.
To stop insects like the Asian Citrus Psyllid or the Light Brown Apple Moth, it may no longer be OK to pick apples or oranges from a backyard tree and drive them to a friend's house if the fruit comes from a quarantine area. Bringing firewood from home might get you turned back at a campground entrance if you live where Asian Longhorn Beetles have taken up residence. Fear of Khapra beetles means if you carry rice from India across a U.S. border, you could pay a $1,000 fine.
"We need to get Americans to start thinking about how these pests are moving around the country," Pfister says. "April's the time of year when people start to go camping and hiking and work in their gardens, so it's a very appropriate time to address this national problem."
The USDA says April is Invasive Plant Pest and Disease Awareness Month.
The nasty 15 includes moths, flies, beetles, ants, a louse, a snail and two pathogens. They range from the Asian Citrus Psyllid, which threatens to destroy the U.S. orange crop, to the Giant African Snail, which will happily munch on plaster and stucco when it can't get to one of the 500 plants it prefers. The Asian Ash Borer threatens the northern white ash trees used to make the famed Louisville slugger baseball bats.
People don't always take the threat posed by these pests seriously, says Ken Gilliland, director of international trade and transportation for Western Growers. His trade group represents farmers in Arizona and California, where much of the nation's fresh produce is grown.
"It just takes one or two people" carrying infected fruit or vegetables to an uninfected area to start an infestation, he says. "They don't see the direct impact they might have, but in the long term they're going to pay for it in higher prices," because of the costs involved in treating crops and inspecting them.
The Asian citrus psyllid, which has caused $4.5 billion in losses to Florida orange and grapefruit growers, got established in California when one person brought a cutting from a citrus plant home from a trip to Asia, Gilliland says: "They shared it with their neighbors, they all planted them, and it ended up resulting in a quarantine of the whole area."
In wilderness areas, bugs are a huge threat and can change forests and tree cover in just a few years, says Chris Martin, Connecticut state forester.
When the Asian Longhorned beetle arrived in Massachusetts, "It's been dramatic. You used to have tree-lined streets, and now these neighborhoods are just devoid of trees," says Martin, who chairs the science and health committee of the National Association of State Foresters.
When regulators started telling people they couldn't take firewood outside of quarantine areas because of the threat of transporting larvae, people balked, Martin says. Many private and state campgrounds in areas where beetles and borers have taken hold no longer allow outside firewood.
"It was like with recycling and seat belts. The government was telling us how to live our lives," he says. "But over time reasonable folks came around."
That's the message the USDA wants to get out: Ordinary Americans can help stop the spread of pests, Pfister says. The USDA website HungryPests.com has suggestions on how to stop the spread of invasive pests.
Gardeners, hunters, campers and hikers are the eyes and ears of state agriculture programs, he says.
"We have citizens all over the country calling us and saying that they've seen something," Pfister says. "Ninety-nine percent of the time it's nothing, but we want those calls, because citizens are our first line of defense."
The most threatening pests:
Asian Citrus Psyllid and Citrus Greening Disease. The size of a chocolate sprinkle, it carries Citrus Greening Disease, which turns fruit bitter. Found in California, Florida.
Asian Longhorned Beetle. Infests and kills hardwood trees. Found in Massachusetts, New York and Ohio.
Emerald Ash Borer. Iridescent green insect destroys ash trees. Found in 18 Midwest and Northeast states.
European Grapevine Moth. In caterpillar stage eats grape flowers and grapes, causes rot. Found in California.
European Gypsy Moth. In caterpillar stage defoliates 300 species of trees and shrubs. Found in 21 states and D.C.
False Codling Moth. Feeds on and destroys fruit trees, plants and field crops. Eradicated in Ventura County, Calif.
Giant African Snail. Up to 8 inches long, it eats paint, plaster and stucco when it can't get any of 500 plants. Can carry a parasite that can cause meningitis in humans. Found in Florida.
Imported Fire Ants. Sting repeatedly, causing blisters. Can kill small animals. Feed on crop plants. Found in 14 states and Puerto Rico.
Khapra Beetle. Eats grain crops and packaged foods. Not found in the United States.
Light Brown Apple Moth. Attacks 250 crops and garden plants. Found in California and Hawaii.
Mediterranean Fruit Fly. In Caterpillar stage, it feeds on nuts and vegetables, making them unfit for human consumption. Found in Hawaii.
Mexican Fruit Fly. Damaging to 50 plants, particularly citrus and mango. Eradicated in California and Texas.
Oriental Fruit Fly. Attacksmore than 230 fruits and vegetables. Found in Hawaii.
Sudden Oak Death. Kills more than 75 plant species, especially oak and California Bay Laurel trees. Found in California, Oregon.