Natural Resources Canada

Forest Pathology in Canada.
English: http://www.nrcan.gc.ca/forests/insects-diseases/13361
Francais: http://www.rncan.gc.ca/forets/insectes-maladies/13362

International Agencies

Commonwealth Agricultural Bureau International (CABI)  
Food & Agriculture Organization (FAO)
United Nations (UN)

Government of Canada

Government of Canada  – Including access to electronic and internet directories

Regulatory Agencies

Pest Management Regulatory Agency (PMRA)
PMRA Label Search  
USA Environmental Protection Agency (EPA)

Canadian Food Inspection Agency / Agence Canadienne d’Inspection des Aliments

CFIA

USDA Animal and Plant Health Inspection Service

APHIS USDA