APHIS Factsheet

Plant Protection and Quarantine August 2010

Attack of the 

Invasive Species

The United States is under attack from alien invaders, 

but they’re not from outer space. They’re foreign plant 

pests, diseases, and weeds, and they’re feasting 

on and infesting America’s agricultural and natural 

resources. They all have one other thing in common: 

They are causing or are likely to cause harm to the 

economy, the environment, or human health. Some 

pests, such as the imported fi re ant, threaten plant, 

animal, and human health. 

 In today’s global marketplace, the volume of 

international trade brings increased potential for these 

invaders to enter our country. Many of these pests 

and diseases have seriously harmed urban and rural 

landscapes and have caused billions of dollars in lost 

revenue and millions in cleanup costs. Some scientists estimate that the economic impacts from invasive 

species exceed $1 billion annually in the United 

States. This is on top of the damage they cause to 

hundreds of millions of acres of native ecosystems 

and associated native plants and animals. That’s why 

keeping these pests and diseases out of the country 

is the number one priority of the U.S. Department 

of Agriculture’s Animal and Plant Health Inspection 

Service (APHIS).

 Just how damaging are invasive species to 

America’s farmland and natural ecosystems? These 

hungry pests grow and spread rapidly, disrupting the 

areas they invade by:

• Pushing out native species;

• Reducing biological diversity;

• Killing forest trees;

• Placing other species at increased risk of 

extinction;

• Altering wildfi re intensity and frequency;

• Damaging crops;

• Closing foreign markets to U.S. products from 

infested areas; and,

• Costing millions of dollars in treatments to industry 

and government.

 If you are a hiker, biker, camper, bird watcher, 

gardener, hunter, fi sherman, boater, rancher, farmer, 

or logger, these invaders could ruin your favorite 

outdoor activity—or your livelihood.

How Do They Get Here?

Although some invasive species can slip into the 

United States naturally via wind, ocean currents, and 

other means, it’s uncommon. Most invasive species 

get some help from human activities. They are 

brought into the country and released intentionally, 

or they are moved and released as an unintentional 

byproduct of cultivation, commerce, tourism, or travel. 

 Many species enter the United States each year 

in cargo, mail, and passenger baggage or as contaminants of commodities. Agricultural produce, nursery 

stock, cut fl owers, and timber can harbor insects, 

disease-causing microorganisms, slugs, and snails. 

These pests can also hitchhike on containers, crates, 

or pallets. Weeds continue to enter the United States 

as seed contaminants.

 Military cargo transport can also bring in harmful 

species such as the Asian gypsy moth and brown tree 

snake. Ballast water released from ships as cargo is 

loaded or unloaded has brought in several destructive 

aquatic species. 

Protecting the United States against 

Invasive Species

APHIS’ job is to protect the United States from the 

entry of these invaders and, if they do slip through, to 

respond rapidly and effectively to minimize the damage. APHIS’ Plant Protection and Quarantine (PPQ) 

program is a key part of this effort. PPQ safeguards 

U.S. agricultural and natural resources from risks 

associated with the entry, establishment, or spread of 

agricultural pests and diseases, as well as invasive 

and harmful weeds. In this battle, PPQ works very 

closely with its many partners at the Federal, State, 

county, and local levels and at universities and nongovernmental organizations.

 To support this complex mission, PPQ:

• Partners with the U.S. Department of Homeland 

Security (DHS) to prevent the introduction of 

agricultural pests and diseases at U.S. ports 

of entry;

• Develops quarantine policies and regulatory 

requirements for agricultural commodities and 

plant resources;

• Establishes requirements for and facilitates the 

safe import and export of agricultural products;

• Monitors and surveys throughout the country for 

pests and diseases;
• Prevents, detects, manages, and if possible, 

eradicates foreign pests and diseases in the 

United States;

• Develops scientifi cally advanced, environmentally 

sound methods to respond to plant health threats; 

and,

• Collects and analyzes pest data, both in the 

United States and overseas, to identify and evaluate pathways for the introduction and movement of 

invasive plant pests and weeds.

 Through these activities, PPQ protects America’s 

agriculture and the environment against pest and 

disease threats. This helps to ensure a diverse natural 

ecosystem and an abundant and healthy food supply 

for all Americans.

What You Can Do to Fight these Invaders

Despite their best efforts, APHIS and its partners 

cannot defeat invasive species by themselves. They 

need you in the fi ght because you make all the difference in this battle. For example, by deciding not to 

move fi rewood on your next camping trip, you might 

just save a forest that could have been ravaged by any 

number of pests—Asian longhorned beetle, emerald 

ash borer, gypsy moth, or Sirex woodwasp—riding 

on or in your logs to uninfested areas. Through your 

actions, you can become an important protector of 

America’s agricultural bounty and natural treasures.

 The simplest and most important thing anybody 

can do to help fi ght invasive species is to prevent their 

introduction and establishment. Invasive organisms 

can easily be transported on living plants or fresh 

products such as fruit. Many pests can be found 

in recently killed plant material including fi rewood, 

lumber, and wood packaging material. Avoiding the 

long-range movement of these materials is a simple 

way to slow the spread of pests. Buying only certifi ed, 

pest-free nursery stock is also a good idea. 

 Based on your outdoor hobbies or your occupation, there are many specifi c actions you can take. 

See the following lists*

 for details.

International travelers:

• Declare all food, live animals, and plant or animal 

products to a U.S. Department of Homeland 

Security Custom and Border Protection officer or 

agriculture specialist at the fi rst port of entry.

• Research the admissibility of plant and animal 

products before your trip. You can call APHIS at 

(301) 734-0841 for question regarding plants and 

(301) 734-3277 for those regarding animals.

• Please keep in mind that certain foods are 

restricted in order to protect community health, 

preserve the environment, and prevent the 

introduction of devastating pests and diseases to 

domestic plants and animals.

• If you suspect agricultural smuggling, please 

call APHIS’ Smuggling Interdiction and Trade 

Compliance Unit at (800) 877-3835.

Hikers, bikers, campers, and outdoor enthusiasts:

• To avoid spreading seed of invasive plants, 

learn to recognize infestations and avoid 

passing through them.

• Clean equipment, boots, animals, and gear 

between trips, or preferably before leaving an 

infested area. Make sure to remove all seeds

 and other plant parts.

• Report any invasive pest sightings to the local

land manager or local APHIS office (click on

the “Report a pest or disease” link at 

www.aphis.usda.gov).

• Always use weed-free hay and feed for 

your animals.

• Don’t move fi rewood. Buy or use fi rewood that 

is close to your campsite. 

Hunters:

• Use only native plants for food plots. Native 

plants provide much better food and cover for 

wildlife. 

• Clean your boots, hunting gear, truck bed, and 

tires after a hunting trip to make sure you are not 

spreading seeds, insects, or spores to a 

new location.

• Don’t move fi rewood. Buy or use fi rewood that is 

close to your campsite. 

• Learn to identify the invasive species in your area. 

Report any sightings to your county extension 

agent or local APHIS office (click on the “Report a 

pest or disease” link at www.aphis.usda.gov).

Gardeners: 

• Always declare any plant material brought in from 

travel abroad.

• Go native! There is a wide variety of beautiful, 

easy-to-care-for native plants available. Look for 

an alternative plant list for your State or region.

• Avoid using invasive plant species at all costs.

• Remove invasive plants from your garden.

• Until you are able to rid your garden of invasive 

plants, be responsible and remember to remove 

and destroy seed heads before they can spread. 

Also, don’t share invasives with other gardeners.

• Talk to other gardeners about invasives and how 

you plan to help in the fi ght against them.

• If you are worried that your garden will lose its 

luster after removing invasives, talk to your local 

native plant society or exotic pest plant council. 

These organizations will be able to suggest 

suitable native replacements. *Many of these lists are compiled from materials prepared by the University of 

Georgia’s Center for Invasive Species and Ecosystem Health. 
The U.S. Department of Agriculture (USDA) prohibits discrimination 

in all its programs and activities on the basis of race, color, national 

origin, age, disability, and where applicable, sex, marital status, 

familial status, parental status, religion, sexual orientation, genetic 

information, political beliefs, reprisal, or because all or part of an 

individual’s income is derived from any public assistance program. 

(Not all prohibited bases apply to all programs.) Persons with 

disabilities who require alternative means for communication of 

program information (Braille, large print, audiotape, etc.) should 

contact USDA’s TARGET Center at (202) 720–2600 (voice and TDD). 

To fi le a complaint of discrimination, write to USDA, Director, Office 

of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 

20250–9410, or call (800) 795–3272 (voice) or (202) 720–6382 

(TDD). USDA is an equal opportunity provider and employer. 

• Report any suspected invasive species to your 

county extension agent or local APHIS office 

(click on the “Report a pest or disease” link at 

www.aphis.usda.gov). 

• If you suspect agricultural smuggling, please 

call APHIS’ Smuggling Interdiction and Trade 

Compliance unit at (800) 877-3835.

Bird watchers:

• To avoid spreading seed of invasive plants, learn 

to recognize infestations and avoid passing 

through them. 

• Clean equipment, boots, and gear between trips 

or, preferably, before leaving an infested area. 

Make sure to remove all seeds and other 

plant parts. 

• Report any invasive sightings to the local land 

manager or local APHIS office (click on the “Report 

a pest or disease” link at www.aphis.usda.gov). 

• Change the water in bird baths often to prevent 

mosquitoes from breeding. 

Ranchers and farmers:

• Learn to identify the invasive species in your area. 

Report any sightings to your county extension 

agent or local APHIS office (click on the “Report a 

pest or disease” link at www.aphis.usda.gov). The 

sooner invasive species are detected, the easier 

and cheaper it is to control them.

• Clean your boots, gear, truck bed, tires, and 

harvesting equipment after working a site to make 

sure you are not spreading seeds, insects, or 

spores to a new location.

• Be sure to control invasive plants along fencerows, 

ditches, and other areas adjacent to fi elds.

• Always use weed-free hay and feed for 

your animals.

• Remove or eliminate from your property any junk 

piles or other places bees can nest.

Loggers and foresters:

• Learn to identify the invasive species in your area. 

Report any sightings to your county extension 

agent or local APHIS office (click on the “Report a 

pest or disease” link at www.aphis.usda.gov). The 

sooner invasive species are detected, the easier 

and cheaper it is to control them.

• Control invasive species before the start of 

harvesting activities (this includes raking for pine 

straw). Invasive plants spread quickly after a 

disturbance. Reducing populations before disturbing them is the best defense.

• Clean your boots, gear, truck bed, tires, and 

harvesting equipment after working a site to make 

sure you are not spreading seeds, insects, or 

spores to a new location.

Commercial producers:

• Never bring nursery stock, budwood, or bees into 

the country unless you have a permit from APHIS 

and follow all permit requirements. Doing so could 

introduce devastating pests and diseases.

• If you suspect agricultural smuggling, please 

call APHIS’ Smuggling Interdiction and Trade 

Compliance Unit at (800) 877-3835.

Hungry to Learn More?

All of these Web sites are great resources:

http://www.hungrypests.com

http://www.beetlebusters.info 

http://www.stopthebeetle.info 

http://www.saveourcitrus.org 

http://www.dontmovefi rewood.org

http://www.invasive.org

http://www.invasivespecies.gov

http://www.aphis.usda.gov/plant_health

http://www.continentalforestdialogue.org

United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture