Bright Yellow Magic traps aphids in the garden!
Aphids and white flies are lured by glittering yellow and can be trapped by placing yellow boards or other yellow enticements – coated with heavy motor oil, petroleum jelly, or Tack Trap – near vulnerable plants. Recoat the traps when they dry out.
Don’t throw away yellow plastic lids that come on some coffee and cat food cans. They turn into good aphid traps. Paint them with honey or a commercial trapping solution. If washed, often, they can be used many times.
from: Rodale’s book of Hints, Tips, & Everyday Wisdom.