Mother Earth News (No. 246) put out the results of what works/doesn't for readers across the states. I won't give the full details but here are a few:
Slugs:handpicking, iron phosphate baits, and
DE Squash Bugs: handpicking, cleaning up infested plants at seasons end
Aphids: pruning off infected parts, insecticidal
soap, attracting beneficials
Imported cabbageworms: Bt, spinosad, paperwasps
Squash vine borers: crop rotation, growing resistant varieties of Curcurbita moschata (solid stems)
Japanese Beetles: handpicking, growing trap crops of raspberries or other fruits
Tomato Hornworms: Bt and handpicking
Cutworms: using rigid collars to protect young seedlings
Grasshoppers: poultry food
Cucumber beetles: neem, handpicking and good garden cleanup
corn earworms: putting a few drops canola/olive oil on the tips of ears right when the silks start to show
Whitefly: insecticidal soap/Dawn dishsoap