Globalization has been pretty much of a disaster for the natural world, moving all kinds of pest insects and diseases to where they have no natural enemies and the plants have no defense against them. Here's a list of pest insects that come in just on imported pine logs: pine loopers, exotic bark beetles, ambrosia beetles, Bark Anobiid of Pine,Sirex Woodwasp, Giant/Dampwood Termites, Drywood Termites,Subterranean Termites. And of course many others by many other routes, the above mentioned varroa mites were imported from Africa in the 1990's, emerald ash borer. Recent imports include Asian citrus psyllid which carries the disease citrus greening, which has been decimating citrus crops, light brown apple moth and on and on. People trying to preserve their crops from these and imported diseases (e.g. anthracnose, sweet orange scab) do more and more spraying and treating with insecticides, fungicides, antibiotics, etc, which just increases the stress on the system.
There's just not enough resources to do the inspections to try to keep all this stuff out. Somewhere else I saw that the rate of new pests coming in has increased significantly since 9/11/2001, because lots of the agricultural inspectors were pulled off of that duty to inspect for possible weapons/ terrorist materials coming in. I suppose eventually some new adaptation/ balance would be worked out, but that would have to occur in evolutionary time periods, thousands of years at least. I don't know if there will be human beings around to see it by then.

