Plantstress  
   Discussions and articles on plant environmental stress, its impact and mitigation in agriculture. Includes news, announcements, events, bulletin board, and reference database.
   http://www.plantstress.com/

New and Emerging Plant Diseases Project  
   Provides agricultural producers with a comprehensive listing of new, emerging and re-emerging plant diseases throughout the world. Lists sorted by disease, host or pathogen.
   http://www.ces.ncsu.edu/depts/ent/clinic/Emerging/

New Zealand Plant Diseases  
   Database of fungal pathogens on trees, shrubs, and herbaceous plants. Search by pathogen, host or recording authority.
   http://www.landcare.cri.nz/science/nzpddb/

Plant Health Australia  
   Commission projects and develop policies to enhance the ability of Australian agriculture to respond to pests, weeds and diseases. Includes corporate and operational plans, projects, members list, publications, and related links.
   http://www.planthealthaustralia.com.au/

Database of Integrated Pest Management Resources  
   Search engine covering a wide array of crops, pests, control tactics, regions, organizations, and related topics.
   http://www.ippc.orst.edu/cicp/

Common Names of Plant Diseases (listed by host)  
   Searchable database of the official names adopted for use by the American Phytopathological Society in its publications. Includes diseases caused by bacteria, fungi, nematodes, phytoplasmas, virus (and virus-like), and miscellaneous diseases/disorders.
   http://www.apsnet.org/online/common/

Database Resource for Analysis of Signal Transduction In Cells  
   Provides an understanding of signaling between plants and pathogens with animated movies and diagrams. Includes database of plant genes regulated in response to infection, and related links.
   http://www.drastic.org.uk/

Guide to Plant Disease Control  
   Resource of many plant diseases, images, and control recommendations from the Oregon state University.
   http://plant-disease.ippc.orst.edu/

Diagnosing Plant Damage  
   A how to approach on accurate diagnosis, with diagrams and photographs.
   http://oregonstate.edu/dept/hort/dpd/index.htm

Verticillium Wilts in Tree Species  
   Information from an EU-funded research project including a compendium on Verticillium wilts in trees (pdf-format), links to the participating groups and a description of ongoing research.
   http://eu-verticilliumintrees.org

Plant Pathology Internet Guide Book  
   Resource for phytopathology, applied entomology and related sciences on topics like pesticides, plant diseases, pest management, plant pathology education, mycology, viruses, bacteria, nematodes, biological control, turf management, and forest.
   http://www.pk.uni-bonn.de/ppigb/ppigb.htm