The Virtual Plant & Pest Diagnostic Laboratory - Perdue University's online FAQ, with an opportunity to mail in your bug for expert identification and analysis. Topics covered
here include molds and slimes, mites and other insects, animal pests, plant diseases, lawn and turf.
Vegetable Pests - University of Kentucky guide to what bugs and insects you're likely to find feasting on peppers, squash, cucumbers and more, and don't miss other sections for tips and advice on getting rid of aphids and white flies.
Garden Pests & Problems - Pioneer Thinking - Content-rich articles like Praying Mantis - Friend or Foe? with tips on natural, organic and homemade remedies plus other common sense ways of dealing with garden bugs and animal pests; related links and resources.
Integrated Pest Management - Here's a great rundown of who or what is causing your tree or flower garden to wilt, damp-off, or rot, including diseases related to specific plants. From Pennsylvania State University.
Also see specific vegetable garden bugs, pests & diseases: