What Effect Does Talcum Powder Have as an Insecticide?
Category: Agriculture—Insect Pest Management
Project Idea by: Thomas Shulanberger
A pesticide is a substance intended to repel, kill, or control any kind of pest (an unwanted organism). Pests include weeds and insects. Pesticides used to kill weeds and insects are called herbicides and insecticides, respectively.
In an effort to kill mosquitoes, the chemical insecticide dichloro-diphenyl-trichloroethane, commonly called DDT, used to be sprayed from planes. It was very effective in killing insects. The problem was that it was not selective and killed good as well as bad insects. It also caused many problems in animals including the loss of calcium from the shells of bird eggs. This loss caused the eggs to be soft and easily cracked, preventing baby birds from developing. In 1972, DDT was banned (forbidden to be used) in the United States. Many other nations have banned it or put it under strict control.
Because of the negative effects of some pesticides, organic pesticides are used by some gardeners and farmers. Organic pesticides are pesticides that come from natural sources, including plants such as marigolds, and minerals such as boric acid.
Boric acid is an effective organic insecticide that kills insects that eat it. Sugar is often mixed with borax to attract insects. Talcum powder is said to be an effective organic insecticide that repels ants. Some report that ants will not walk through the powder. How much powder is needed to stop the ants? Is it the depth of the powder or the width of the trail that makes the powder an effective ant insecticide? Does talcum powder repel other insects? A project question might be, "What effect does talcum powder have as an insecticide?"
Clues for Your Investigation
Design a method for testing the effectiveness of talcum powder as an insecticide. One way is to catch and count insects in areas surrounded by various amounts of talcum powder as well as an area with no powder. Since some insects are harmful, including some ants, the collecting method must be safe, such as an insect—collecting trap. You can prepare a trap by digging a hole in the ground large enough to hold a plastic jar. The top of the jar should be just barely above ground. Place a ring of talcum powder around the open mouth of the jar. For each testing site, vary the width of the powder ring but keep the depth the same. The control will have no powder. After a predetermined time, secure labeled lids on each jar that identify the width of the powder ring. Then lift the jars out of the ground and count the insects inside. The testing sites should all be in the same general area. Release the captured insects in the area they were caught
Independent Variable: Width of the talcum powder ring around an insect trap
Dependent Variable: Number of trapped insects
Controlled Variables: Type of powder, concentration of powder in the rings, type of collecting jar, and environmental conditions
Control: Collecting jar without powder
Other Questions to Explore
- Foods, including onions, garlic, and cayenne (red) pepper, are said to be insecticides. Do these insecticides kill or repel insects? How effective are these foods? Are they specific for one insect?
- How effective are plants such as marigolds as an insecticide? Do they repel or kill insects?
Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state’s handbook of Science Safety.