Red imported fire ants have been successfully kept out of Delaware by inspection and eradication efforts of Delaware Department of Agriculture. A recent detection was made in palm trees shipped in from Florida. http://news.delaware.gov/2017/05/22/care-is-urged-after-red-imported-fire-ants-found-in-palm-tree-shipment/. Plants shipped across state lines should be inspected and come from reputable suppliers.
05/21/17 NFG