Symptom	Plausible Causes	Suggested Treatment
Black spots with yellow halos on leaves	Environment or Disease Bacterial leaf rot
Corn ear galls	Environment or Disease Corn smut
Dark brown or black spots on leaves	Environment or Disease Early blight, late blight
Defoliation	Pests Grasshoppers, hornworms, Japanese beetles, parsley worms
Discolored leaves	Environment or Disease Aster yellows, club root, purple blotch, white mold Pests Carrot rust flies
Discolored lesions on vegetables	Environment or Disease Early blight, late blight
Distorted roots	Environment or Disease Aster yellows Pests Carrot rust flies
Leaf holes	Pests Cabbage worms, cucumber beetles, grasshoppers
Malformed vegetables	Environment or Disease Aster yellows, potato scab Pests Blister mites, corn earworms, cucumber beetles
Nodules on root	Pests Root knot nematodes
Ooze in root	Environment or Disease Bacterial soft rot
Orange bumps on leaves	Environment or Disease Rusts
Plant wilting	Human Causes Inadequate watering Environment or Disease Bacterial wilt, club root, white mold Pests Squash vine borers, wireworms
Small leaf galls	Environment or Disease Edema
Tunnels in vegetables	Pests Carrot rust flies, codling moths, corn earworms, wireworms
Water soaked leaf spots	Environment or Disease Anthracnose, bacterial leaf spot, edema, purple blotch