Pyrethrins are natural insecticides found in pyrethrum daisies like the Dalmatian and Persian chrysanthemums. They work by penetrating a bedbug’s nervous system and paralyzing it. According to entomologists at the University of California in Berkeley, pyrethrums are the first choice for bedbug control, but some bedbugs have mutated and are resistant to pyrethrins. If the bedbug population in your house carries resistant genes, pyrethrins may be ineffective against them.
Bedbugs are small, flat, blood-sucking insects that are active at night. During the day, they hide in cracks found in walls, floors and furniture. Bedbug bites are extremely itchy, but they don’t spread disease. These pests often enter homes on used articles or in suitcases following a trip. Once they infest a building, they can be very difficult to control. Using a combination of methods is usually the most effective way to get rid of them. Fortunately, there are several ways to control bedbugs with natural ingredients that don’t contain poisonous chemicals.
You can make a natural insecticide with Dalmation or Persian chrysanthemums. Both species contain pyrethrins, but Dalmatian chrysanthemums contain more. To increase pyrethrin levels, hang flowers upside-down in water for about 48 hours before drying them. Flowers can be coarsely crushed or made into a fine powder. A fine powder will work better, but the pyrethrins in it will break down more quickly. Make a spray by soaking seven-tenths ounce of dried, crushed flowers in 1 1/2 gallons of warm water for approximately 3 hours. Apply pesticide to cracks and crevices of walls, floors and furniture.
Diatomaceous earth (DE) is an effective way to control bedbugs in areas with a low humidity. It works by absorbing the oils and fats in the outer, protective layer of a bedbug’s skin, causing it to die of dehydration. The sharp edges on the diatomaceous earth also cut through the bed bug’s exoskeleton, increasing the dehydration. Diatomaceous earth is the fossilized remains of one-celled plants. It can be used alone or in formulations that contain pyrethrins. Formulations without pyrethrins are very low in toxicity to mammals. Only use natural diatomaceous earth, or food grade DE, which is often sold as “Fossil Shell Flour.” Don’t use pool grade DE, which is made differently and is toxic. Apply DE to cracks and crevices where bedbugs hide. It can also be sprinkled on carpets.
Bedbugs die when the temperature rises above 106 degrees Fahrenheit, so heat can be an effective way to control them. Clothes and infested bedding materials can be placed in a heated dryer. Mattresses and crevices that are otherwise difficult to treat can be steamed with high temperatures. Large commercial heaters can be used to heat an entire room to around 115 degrees. You can also place the contents of a room inside a Styrofoam box and use household oil-filled heaters to heat the area to a temperature between 113 and 115 degrees Fahrenheit.
Reducing the number of bedbugs before treatment will increase your chances of eliminating the rest of them. Vacuum infested areas, including carpets, mattresses, box springs and furniture. When you’re finished, remove the vacuum cleaner bag, seal it in a zipper-lock bag, and place it in a deep freezer for one week before disposing of it.
- Penn State College of Agricultural Sciences Entomology: Bed Bugs
- University of Florida IFAS Extension: Bed Bugs and Blood-Sucking Conenose
- University of Nebraska – Lincoln: Managing Bed Bugs
- University of California Berkeley Understanding Evolution: Bed Bugs Bite Back Thanks To Evolution
- McGill University Ecological Agricultural Projects: Home Production of Pyrethrum
- Extension Toxicology Network: Pyrethrins; March 1994
- Washington State University: Pesticidal Dusts
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