United States Department of Agriculture-Animal and Plant Health Inspection Service
Plant Protection and Quarantine-Center for Plant Health Science and Technology

More recently, increasing air traffic and tourism and shipment of containerized cargo have provided new pathways of entry. Containers make cargo less accessible to port inspectors and allow movement of cargo into the country's interior. Despite the apparent increase in the risk of pest introductions through containerization, its impact is not easily evaluated (McGregor 1973). The Asian tiger mosquito (Aedes albocinctus) is a recent introduction of much public concern because of its potential in transmitting viruses that cause human disease e.g., dingue fever. Its entry into the United States has been traced to used tire casings imported from Asia.

Other items that seem to present a particular threat are imported cut flowers and dried plant material imported by florists (thrips, various cutworms and other moths), subtropical and tropical fruits and vegetables (thrips, fruit flies), and timber (bark beetles). As patterns of trade continue to change, we can expect the sources of non-indigenous pests to change as well (CAST 1987).

Movement of plant material continues to be a major concern. Not only does it allow new pests to enter the country, but the high volume of traffic in nursery stock and house/yard plants results in the movement of established immigrants insects throughout the United States.

(All text on this page is from Kim & Wheeler's 1991 report.)