LINCOLN, Neb. (AP) — Nebraska residents who use firewood are being asked to buy locally harvested wood to keep plant diseases and insects from spreading.

The Nebraska Department of Agriculture says plant pests can travel through firewood, and could the state's trees. State officials are trying to prevent the spread of the Emerald Ash Borer, a destructive beetle species, and Thousand Cankers Disease, which threatens some walnut trees.

Nebraska state entomologist Julie Van Meter says the Emerald Ash Borer has been found in Iowa, Missouri and Kansas.