Is the mighty cedar the key to all natural pest control? Oh, we’ve known of its ability to protect clothing from moths for centuries, but cedar actually does a lot more. In fact, it is a proven poisonous deterrent to rodents, cockroaches and many species of ants, including fire and crazy. Cedar does not affect spiders, as they are arachnids, not insects. Be aware that all cedars are not equal when it comes to toxicity, so buyer beware. Western Red Cedar mulch, shavings and sawdust are by far the cedar products of choice, and therefore the most expensive. In addition to cedar’s pesticide properties, it is very resistant to rot, mold and moisture.
The secret to cedar’s ability to run off a whole host of unwanted critters are aromatic hydrocarbons (phenols) and acids it contains that are toxic. The phenols, which give cedar its delightful earthy scent, are what repels fleas, moths, cockroaches, venomous snakes, mice and rats. And, in the laboratory, autoclaved cedar shavings have even been shown to inhibit the growth of micro-organisms. When rodents are exposed to cedar mulch/shavings/sawdust, the aromatic hydrocarbons are absorbed through the respiratory tract and enter the blood, damaging livers. The acids given off by cedar are very damaging to rodent respiratory tracts, destroying cells that line the lungs and trachea.
Be forewarned pet owners, it is highly recommended that cedar (and some types of pine) shavings or products are never used for pet insects or rodents, especially as a bedding material for mice, rats, gerbils, guinea pigs, rabbits, etc.. In urban areas where rats have invaded, the use of cedar will not only drive off the unwanted pests, one study* showed that the mortality of rat pups exposed to cedar shavings was tremendously high compared to rat pups exposed to corn cob or aspen shavings. Of the pups exposed to cedar shavings, 56% were dead by 2 weeks of age, while only 0.01% of the pups raised on the other bedding died. The cedar-raised pups also weighed about 23% less than the other pups.
There are reported successful cases where cedar was used for bedbugs as well, but this use has not been scientifically verified. Cedar is safe for use around domestic pets such as cats and dogs, though they should not be allowed access to cedar shavings/sawdust products being used to rid pests inside the home. Never use cedar products as toys for pets. Cedar mulch used for exterior purposes offers little danger to cats or dogs, but exposure should still be controlled. Cedar use around persons with asthmatic conditions should be discouraged, as it has a slight potential to cause adverse reactions.
So, if you are in the market for an all natural product to deal with ant, cockroach and/or rodent infestations, be sure to put cedar products on your list. A few tips when buying products; Cedar is available in small blocks, as hangars, ball and sachets, which are made with either sawdust or shavings. Cedar sawdust is much denser and heavier than shavings, and retains its deterrent properties much longer. Also, be careful to only purchase 100% pure products (some may use pine, aspen, cypress, etc. as fillers). Cedarwood oil is a mixture of organic compounds considered generally safe by the US Federal Drug Administration as a food additive preservative. The US Environmental Protection Agency believes there is negligible human environmental risk posed by exposure to registered cedarwood pesticide or food preservative products, if used in properly prescribed manner.
Cedar oil is ranked as a pesticide in Canada, and can only be applied by licensed technicians. In the USA, cedar oil is available in several concentrations, and from small, highly concentrated vials of oil used for aroma therapy, to less concentrated one gallon and larger volume containers for wood preservation/restoration use, or as a pesticide. Be cautious with the use of cedar oil in visible areas, especially for interior use, as it may leave a residue that could attract dirt. Cedar Oil Blend was developed for the United States Army, to create a bio insecticide to control parasite (fleas, ticks, bed bugs, lice and mites) problems being experienced by troops deployed to the Middle East, without ugly side-effects.
So, all hail the mighty cedar, a wonderful wood that mankind has revered for centuries. It has housed us, entertained us, transported us across water, kept our possessions safe and dry, and has rid us of unwanted pests. While there may be woods than are considered more beautiful, more durable, and more popular, Cedar reigns as the absolute monarch of multitasking woods. For those planning projects, from building a home to landscaping, be sure to incorporate cedar to prevent rot and pest infestations. You’ll be very glad you did.
* – Burkhart, Carol A. & Robinson, James L., (1978) High rat pup mortality attributed to the use of cedar-wood shavings as bedding. Laboratory Animals, 12, pg. 221-222