Invasive species are all around the world, they don't have natural predators and devastate local ecosystems.
But Iowa has two invasive insects that are set to cost billions of dollars in damages to rural and urban agriculture. The Emerald Ash Borer kills Ash trees and the brown marmorated stink bug eats crops, including corn and soybeans.
Both are hard to get rid of, and according to State Entomologist Robin Pruisner, humans are the reason both species get around the country so easily.
"They're hitchhikers, so they like to move whether it's inadvertently or on purpose on something you may pick up and bring with you."
Alongside being hard to control and easily spread, Iowa State University Forestry Professor Janette Thompson says creatures like the Emerald Ash Borer are hard to find. She says the bugs can hide in a tree for four years before showing themselves.
Thompson says, "It's sneaky that way, and we're still not used to that. It still surprises us that, you know, you find a bug and then, 'Oh my gosh, look, it must have been here a while.' So that's just the way it is. That's just the way it kind of shows up. It's a cumulative effect on a tree and it's a tiny bug."
Thompson says when they look at a map of spreading Emerald Ash Borers it's easy to correlate human highways with bug traffic. Pruisner says it's the same way with the brown marmorated stink bug.
"And so it is very famous for getting into a box, into your car and just going and riding along with you so it's moved by humans, we've had reports of people who are buying things off the internet from the east coast and when they get the box in the mail it's also full of brown marmorated stink bugs."
Iowa DNR estimates the Emerald Ash Borer will cost Iowa communities between several thousand and a few million dollars each; the cost to the nation as a whole is estimated at $120 billion. The brown marmorated stink bug poses a risk to $21 billion in U.S. crops.