Many invasive species can be found in the United States. Some are exclusive to particular areas, while some are more widespread. In addition to the national list put out by the USDA, individual states often have their own lists as well.

Because invasive species are such a problem in many areas, a variety of strategies have been developed to combat these organisms. Control methods have to be carefully chosen so that further damage to the ecosystem does not result. One such control method is biological control. In this method, organisms that are predators of the invasive species are often used to help control the size and spread of their populations. If not studied extensively before use, negative side effects can occur. For example, Hawaii had issues with an invasive species of snail (the Giant African Snail), so a cannibal snail, the Rosy Wolfsnail, was introduced to the island. Rather than feeding solely on the Giant African Snail, they preferred the already struggling native populations of snails, thus causing further damage. Check out this video of the feeding habits of the Rosy Wolfsnail.

To avoid similar situations, careful consideration must be used when selecting the type of control strategy to employ. Before combating the Hemlock Woolly Adelgid (an invasive insect that is destroying Hemlock stands) with beetles to be introduced from Asia, scientists studied them closely to ensure that the beetles would not themselves destroy the ecosystem. They had to make sure that the beetles would prefer the Hemlock Woolly Adelgid over other native species and would also be eaten by predators living in the area so that they would not overpopulate. This article and video provide an account of the use of the predatory beetles in Woolwich, Maine.