Further research tells me : "…termite control is required in all states except Alaska, Maine, New Hampshire, Vermont, Michigan, (except the very southern part), Wisconsin, Minnesota, North Dakota, South Dakota, Montana, Wyoming, Washington, Oregon, Idaho and the northern parts of Nevada, Utah, Colorado, Nebraska, Iowa, and New York." From "Houses: the illustrated guide to construction, design & systems", by Henry S. Harrison.) Found here on Google Books

I think we won't worry overmuch.