Have Mosquitoes? Now, Which Repellent to Use?

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Posted on June 12th, 2012 by Ray Eckhart in Consumers

Ray Eckhart is a Penn State Extension Educator in Franklin County with responsibilities for Consumer Horticulture, Forest Pest Management, and Vector Management (Ticks and Mosquitoes).

Brenna Litynski’s, 10, of Venetia, Pa – 2012 Fite the Bite Poster Winner

Now that the itchy summer season is upon is, Sharon thought it would be a good idea to discuss one of the ways to protect yourself from ticks, mosquitoes, and other biting critters through the use of repellents. The first thing to know is that the U.S. Environmental Protection Agency (EPA) classifies repellents as pesticides, and all the labeling laws and regulations pertaining to pesticide use are also applicable to repellents. So, just as you do with pesticides, “Be sure to read the label and follow the directions carefully.”

EPA’s Insect Repellent Use and Effectiveness database lists over 650 products registered for use as a repellents, but there are really only a handful of active ingredients used in making these products. By far the most widely used active ingredient is the compound DEET, which is short for the scary sounding compound N,N-Diethyl-meta-toluamide, but don’t let the name put you off (heh!).

Although newer chemicals have been approved for use as repellents on skin in recent years, DEET is still the gold standard for effectiveness and overall safety. The American Academy of Pediatrics (AAP) notes that repellents containing up to 30% concentrations of DEET can safely be used on children over the age of 2 months.

After DEET was developed by the U.S. Army in 1946, it was registered for use by the general public in 1957. The percentage of DEET in the product determines the length of time that the product will remain effective. A single application of a product containing a 30% concentration is effective for up to 8 hours. That’s a useful point to remember when reading claims about products containing other active ingredients. Several of them will be as effective as DEET for the first hour or so, but will require re-application to remain effective. Until recently, DEET’s effectiveness was thought to be a function of blocking the mosquito’s ability to detect a nearby host. Recent research from the University of California Davis, however, shows that “DEET doesn’t mask the smell of the host or jam the insect’s senses. Mosquitoes don’t like it because it smells bad to them.” A true repellent.

In 2001, EPA registered Picaridin as another active ingredient that could be used in products marketed as a repellent. The first products appeared in the American market in 2005. To the best of our knowledge, picaridin stimulates sensory hairs on the mosquito’s antennae, and this appears to prevent the mosquito from recognizing its host’s cues.

EPA characterizes the active ingredients DEET and Picaridin as “conventional repellents” and Oil of Lemon Eucalyptus (PMD), and IR3535 as “biopesticide repellents”, which are derived from natural materials, but don’t let that “natural” word fool you. Stay tuned to next week’s blog to learn more about the “natural” products.

Before we end, we wanted to give a shout out to Brenna Litynski from Venetia, Pennsylvania for the great poster she designed for the Fight the Bite Poster Contest. Brenna was the NATIONAL 5th grade winner!

Until next time,
Be Safe!

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References:

Active Ingredients Found in Insect Repellents. U.S. Environmental Protection Agency. (2009)

Gervais, J. A.; Wegner, P.; Luukinen, B.; Buhl, K.; Stone, D. Picaridin Technical Fact Sheet. National Pesticide
Information Center, Oregon State University Extension Services. (2009)

Gripp, S.I., Jacobs, S.B., and Hock, W.K. Using Insect and Tick Repellents Safely. The Pennsylvania State University. (2005)

Groundbreaking UC Davis Research Shows DEET’s Not Sweet to Mosquitoes. University of California, Davis. (2008)

Updated Information Regarding Insect Repellents. Centers for Disease Control and Prevention.

Using Insect Repellents Safely. U.S. Environmental Protection Agency.