From the Missouri Department of Conservation
-- The potential effects of invasive plants, animals and diseases on the state’s economy and outdoor resources are incalculable, according to the Missouri Department of Conservation. The department is encouraging residents to save state forests, fish and wildlife resources and state economy from an army of invasive species.
Missouri’s location in the middle of the continent makes it a crossroads for travelers of all kinds, including a growing number of exotic plants, animals and diseases. Among the better-known invaders are the zebra mussel, gypsy moth and bush honeysuckle. But, the list is much longer. Here are some key culprits:
Emerald ash borer
These penny-size green beetles were first discovered in southeast Missouri in 2008. They have already killed more than 50 million ash trees in 14 states, including Missouri. Ash trees make up approximately 3 percent of forests and 14 percent of urban trees in Missouri. In some neighborhoods and parks, that figure reaches as high as 30 or 40 percent.
The adult beetles nibble on ash foliage but cause little damage. However, the larvae feed on the inner bark of ash trees, disrupting the tree's ability to transport water and nutrients, eventually killing the tree.
The MDC is working with other state and federal agencies to help stop the spread of the beetle. A quarantine is in effect in Wayne County that restricts movement of hardwood firewood, ash nursery stock and other untreated ash wood products out of the county.
Residents can help prevent the spread of this deadly invader by not transporting firewood. Get firewood where you will burn it, and burn it all before you leave.
Thousand cankers disease
This infection of walnut trees is caused by the walnut twig beetle and a fungus it carries. It affects many types of walnut trees to varying degrees, but is lethal to black walnut. It is killing black walnut trees in at least eight western states.
The beetle bores into walnut trees and the fungus then forms thousands of growths, called cankers, under the bark. These cankers disrupt the tree's ability to transport water and nutrients, and can eventually kill it.
Missouri is home to more than 55 million black walnut trees and is the nation’s leader in black-walnut nut production. Missouri is also one of the largest producers of black walnut wood products. While the disease has not yet reached Missouri, estimates of potential damage to the state’s economy—through the loss of nuts, wood products and planting stock—could annually exceed $135 million.
The Missouri Department of Agriculture has banned the importation of raw walnut wood products, such as firewood, green lumber and nursery stock, from states where the disease has been found. The quarantine does not include nuts, nutmeats, bark-free, kiln-dried lumber and finished products, such as furniture.
Again, don’t transport firewood. Get it where you will burn it, and burn it all.
The rusty crayfish as an invasive species has been spread from its native range in the Ohio River basin by anglers and bait dealers. Its aggressive nature and fast growth rate enable it to displace native crayfish, reducing the biological diversity of Missouri streams.
Residents can help by not dumping bait. The Wildlife Code of Missouri prohibits the release of unused bait into waters where it did not originate and prohibits the sale and possession of this invasive crayfish.
Chinese mystery snail
This large Asian mollusk already inhabits several Missouri streams. It competes with less robust native snails, which are important parts of the food chain. Chinese mystery snails are on Missouri’s list of prohibited species and are illegal to possess.
Residents can help by not dumping aquarium water or contents into Missouri’s lakes and streams. Dispose of unwanted aquarium animals humanely and deposit them in your trash.
This 2-foot-long Asian import has gained a foothold in southern Arkansas and could spread north into Missouri. It can travel cross-country to new waters, sports a mouth full of needle-sharp teeth and devours game fish, such as bass, sunfish and catfish.
This species has multiplied dramatically since invading the Missouri and Mississippi rivers about 20 years ago. They compete with important native aquatic filter feeders and can eventually take over bodies of water. Their impact on Missouri’s commercial fishing industry and sport fishing still is largely unknown, but could be devastating.
This non-native member of the aster family takes over pastures and roadsides, rooting out native plants and ruining pastures for cattle. The 2-foot-tall perennial, bedecked with attractive, fringy pink blossoms, probably arrived in the United States in the late 1800s in contaminated hay or seed from Eurasia. Since then, it has spread to more than 45 states, including Missouri. Unlike aster species native to Missouri, spotted knapweed’s roots produce chemicals that are toxic to other plants, killing native species. It is bad news for wildlife and livestock because it is not a good food plant.
It was designated a noxious weed by the Missouri legislature in 2008. Residents can help by controlling it on their property.
Native to Europe and Asia, purple loosestrife was first brought to North America in the early 1800s. This attractive but highly invasive plant turns diverse, healthy wetlands into impenetrable stands of vegetation largely useless to native Missouri wildlife. Native wetland plants die out due to shading from the tall, dense purple loosestrife stands.
Purple loosestrife is included on Missouri noxious weed list. Residents can help by controlling it on their property.
Common and cutleaf teasel
This pair of prickly thistles from Europe has been in Missouri for more than 100 years, but has multiplied dramatically in the past 10 years. It was introduced to North America, possibly as early as the 1700s, because the prickly stem was used in the textile industry to raise the nap of woolen cloth. Teasel’s unusual—and by some perspectives, attractive—flower heads have led to its use as a horticultural plant, in flower arrangements and in the craft trade. These are extremely aggressive plants that can take over livestock pastures and open fields, displacing even a thick stand of fescue.
Again, these are noxious weeds so it is important to control them if a resident finds them on his or her property.
These hogs gone wild destroy wildlife habitat and private property, compete with native wildlife for food, and can pose a threat to humans, pets and domestic livestock through the spread of disease. Small populations of free-roaming domestic hogs have been part of the Missouri countryside since the days of open range. These isolated populations were kept in check by local hunting efforts.
The situation took a turn for the worse in the 1990s when hog hunting for recreation began to gain popularity. People started raising and releasing European wild boars for hunting on private land. Some escaped, or were intentionally released on public land, and crossbred with existing free-roaming swine.
These hogs gone wild are prolific breeders and their numbers are growing at an alarming rate. Left unchecked, feral hogs will spread throughout Missouri, causing million of dollars in agricultural, environmental and property damage.
The Department of Conservation has been working with other state and federal agencies to control feral hogs on public lands, and is helping private landowners trap and kill them. Hunters are encouraged to shoot feral hogs on sight.