They came like the ash borer, in pallets.

Inside of shipping containers, and these things go all over the world.

And when people make pallets and other wood packaging material, they usually look for the most inexpensive wood that they can find, [laughs] and usually the most inexpensive wood has insects in it.

Andrew says it'd be easiest if we could just reverse time.

Some of the most damaging organisms were actually introduced intentionally.

In the late 1800s and early 1900s, there were organizations called naturalization societies.

People had the idea that you could improve nature by introducing plants and birds and other species from one part of the world to another.