Damage from non-native insects is costing taxpayers billions a year, according to a new study published today in the PLoS One journal. Conducted by a group of U.S. and Canadian scientists and the U.S. Forest Service the study estimates that the invaders cost governments and homeowners almost $4 billion per year. It’s a double-whammy for homeowners who are also sustaining property value losses.

"It is costing taxpayers billions as the government tries to eradicate these invaders," says Betsy Von Holle, a University of Central Florida Biologist and one of the authors of the study. "We're losing a variety of native species as a result of importing these pests. It's not just aesthetics. It's impacting our economy and our analysis shows just how much it is costing all of us, not just government."

The authors looked at three types of invasive pests that feed on U.S. trees, the emerald ash borer, gypsy moth, and hemlock woolly adelgid. When they calculated the economic damages, the costs were staggering. Local governments spend more than $2 billion per year and residential property value loss due to forest insects averages $1.5 billion a year, according to the researchers.The federal government spends on average about $216 million a year.

Wood-boring insects such as the emerald ash borer, which often hitch a ride in packing materials, cost the most to control and do the most damage. But foliage feeders and sap feeders cause an estimated $410 million and $260 million, respectively, in lost residential property value each year. The researchers say that at least 455 types of non-native insects have established themselves in the U.S.

While there is little an individual homeowner can do, the researchers say that their information can be used in cost-benefit analysis to help governments establish import taxes or fees that can be used to fund prevention and eradication efforts.