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Invasive species of Indiana: What you need to know


Invasive species are organisms that move into a habitat that is not naturally where they occur. Invasive species can be both plants and animals. Some invasive species you may have heard of are garlic mustard, multiflora rose, autumn olive, Emerald Ash borer, Asian carp or zebra mussels. These species have moved into Indiana through a variety of methods.

Garlic mustard came to the United States through Michigan, used as a cooking herb, and quickly grew out of control as it could out-compete native species of plants for nutrients and water. Since garlic mustard spreads so rapidly, constant pulling of the plant happens in parks throughout Indiana. This plant takes over habitat from species that commonly occur in Indiana. Garlic mustard, as its name suggests, smells garlicky and is edible. Spreading garlic mustard to other locations is a risk as native plants cannot compete with it and it has no known natural predators (read “How to Eradicate Invasive Plants” by Teri Dunn 581.62 Dun or “Weeds of the Midwestern United States and Central Canada” by University of Georgia Press 632.5 Wee).

The Emerald Ash borer is a beetle that kills ash trees by girdling them under the bark. The ash borer first arrived in the Midwest via the Great Lakes. They came on ships that carried shipping crates from Asia where the insects stayed hidden inside the wood. There is no cure for an ash tree when an emerald ash borer invades (despite what arboriculture specialists say). Treatments are seldom successful, as, by the time EAB is noticed, it is usually too late. The female lays the eggs under the bark, and the larvae eat the cambium, or growing layer of bark until it chokes the tree by stopping the vertical movement of water and nutrients — the tree slowly starves (check out “1001 All-Natural Secrets to a Pest-Free Property” by Myles Bader 632.7 Bad).

Asian carp have been found in the Wabash River, so much so that boaters must be careful on the water while running their boat motors as the disturbance in the water causes the fish to leap out of the water, potentially injuring innocent recreationists. This fish too, can prey upon resources and quickly use them up, keeping native fishes from accessing fresh water and food. These fish are very dirty and cloud the water, reducing water clarity and quality (for more on types of fishes in the United States, look into the “National Audubon Society Field Guide to Fishes” 597.097 Nat).

Zebra mussels have been in Indiana for decades as well. These mussels first arrived in the U.S. via ships as the mussels clung to the hull of the vessels. Zebra mussels invade our fresh water, again outcompeting native organisms for algae. This mollusk also attaches itself to native mussels, incapacitating them. Zebra mussels are so prolific that power plants spend millions of dollars removing the mussel from clogged water intake valves (look into “The Illustrated World Encyclopedia of Freshwater Fish & River Creatures” by Daniel Gilpin 591.76 Gil).

At CDPL, we have a variety of books about animal and vegetal invasive species from which to choose such as “Controlling Garden Weeds” by Barbara Pleasant (EBook on Libby/Overdrive); “How Invasive Species Take Over” by Janey Levy (EBook on Hoopla); and “Invasive Species” by Lisa Amstutz (EBook on Hoopla). For even more information, check out the Indiana DNR Division of Forestry, Division of Entomology or Division of Water for more details.

Want to learn more? Stop by the Reference desk on the second floor at CDPL. You may also send us your questions by email at or give us a call at 765-362-2242, ext. 117.


Stephanie Morrissette is a library assistant at the Reference & Local History Department at the Crawfordsville District Public Library.


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