Descriptions of plant pests under APHIS management.
Resources

USDA. Animal and Plant Health Inspection Service. Plant Protection and Quarantine.

National Plant Board
A non-profit organization to foster effective and harmonized plant health programs with representatives from regional, state, and national organizations.
USDA. Agricultural Research Service.
Integrates the USDA's programs and strategic planning pertaining to pest management, and coordinates the Department's role in the pesticide regulatory process and related interagency affairs.

North Carolina State University
Guide to insect systematic resources. The site includes general information; links to insect collections; identification tools; organizations; and educational resources.