Understanding and controlling nonnative forest pests in the South
lnvasive nonnative forest pests are multiplying and spreading in every forest type in the Southern United States, The costs of controlling these pests have become extremely high, and the damage they cause to ecosystem composition, structure, and function continues to increase. Plants imported for potential release for forage, crops, soil reclamation, and ornamental purposes are not evaluated for invasiveness. Insect pests and diseases arrive in infested nursery stock, woodproducts, pallets, and dunnage, in spite of our regulatory system, which has been overburdened by the rapid increase in international trade. The biological basis ior the invasiveness of nonnative pests andpossible means for dealing with them are discussed.