Sticky traps are a good way to identify what type of pest is attacking house or garden plants. They are usually not enough to control an infestation, but they can also be part of a successful multifaceted approach and may even provide enough control to keep a plant healthy if the infestation is only small.
Color is the main attractant in most sticky traps. Yellow is the color that most garden, lawn and houseplant pests find attractive. Aphids will seek out yellow. Whiteflies, leaf miners, apple maggot flies and leaf hoppers are also attracted to the color yellow. The source of the yellow color is not important. It can be paper, card stock, paint or plastic as long as it is a bright yellow. Consider the color as the bait and make it as bright and noticeable as possible.
Since miniscule insects are trapped by sticky traps, the base material does not need to be very strong. It does, however, need to be able to withstand the conditions in which it is placed. Indoors or in protected garden areas paper or card stock may be suitable for one-time use traps. Most outdoor areas and re-usable traps need sturdier materials such as wood, masonite, plastic or glass. Pieces of slick plastic and glass are easy to clean and re-use, but cannot be hung or staked like wood and masonite.
For easy cleaning, a thin coating of motor oil on the base surface will create a surface that is not necessarily sticky to the touch but is sticky to the pests in the sense that it holds them in place on the trap. Equal parts petroleum jelly and liquid laundry detergent also make an effective coating that is easy to wash away. For a sticker coating, use a commercial insect trap coating available in cans from gardening home improvement stores, or mix together equal parts water and corn syrup and bring it to a boil and then brush it on the trap.
Construction of a sticky trap is simple. For paper or card stock traps, simply cut to the size desired, coat with a sticky substance and set the paper near the infested plant. Punch a hole through the top and tie on a piece of string to create a hanging trap. Wood or masonite traps can be built using 1/4- to 1/2- inch wide by two to three feet long pieces painted bright yellow. Drive the wood or masonite into the ground near the infested plant and coat with a sticky substance. Glass or plastic should simply be coated with a sticky substance and laid flat near the plant.