Invasive Species Resources

See also: Information Bulletins on other vectors/pests

Humans adores trees. But humans also migrate and trade, habits that led to the accidental introduction of insects and diseases that harm trees and alter the landscape. Examples are easy to find and may be outside your front door: American elms that once dotted streets across America succumbed to Dutch elm disease. Now all colors of ash species – black, green, white, pumpkin, and blue – are threatened by emerald ash borer. The already uncommon butternut tree, also known as white walnut, faces the possibility of extinction from a mysterious attacker. Many invasive insects and fungi come from regions where native trees have evolved to resist their attacks. When these species enter the United States, they find trees that lack this resistance. There's no immediate end to this dismal pipeline, but there is hope on the horizon.

Agricultural Research Service (ARS) scientists are tracking a honey bee killer, and their investigations have taken them from hives in Tucson, Arizona, to Bismarck, North Dakota. Led by ARS entomologist Gloria DeGrandi-Hoffman, the team is staking out hive entrances and monitoring the comings and goings of foraging honey bees, which may be the killer's unwitting accomplices. None of the busy little winged bearers of pollen and nectar will get by without inspection: The prime suspect—an eight-legged, pinhead-sized parasite called the Varroa mite—seems to be sneaking into the hives on the bees' bodies. The Varroa mite, Varroa destructor, is considered public enemy number one to honey bees nationwide. The parasite feeds on the blood of adult bees and their brood, weakening them and endangering the entire hive when infestations become severe. But the mite also poses an indirect threat to more than 90 flowering crops that depend on bee pollination, including almonds, apples, blueberries, cherries, and cantaloupes.

Emerald ash borer (EAB) is an invasive insect from Asia that kills ash trees. EAB was first detected in North America in 2002. Several tiny wasp species are helping to control EAB.