With DEET appearing ineffective as a tick-repellent, and permethrin hard to come by, expensive, and a potential neurotoxin, some researchers have turned their attention to botanical oils and their effectiveness in tick control. Products identified as insect repellents are regulated by the US Environmental Protection Agency (EPA) but botanical insect repellents do not, currently, fall under that jurisdiction so caution is needed in such cases. There are possible dangers from neurotoxins in plant-based insecticides as well as from conventional insect repellents, with rosemary oil a potent neurotoxin if ingested in sufficient quantity. It is not safe to assume that herbal insecticides are innocuous as some are extremely powerful and possibly dangerous if used incorrectly.
Natural Tick-Repellents – Do they Work?
One study carried out in Maine (Rand, et al, 2010) looked at IC2, “a minimal-risk (25B) botanical compound” containing 10% rosemary oil in comparison to a commonly used synthetic product bifenthrin, and a water control test. The botanical compound performed as well as bifenthrin with no ticks found on the treated grids within two weeks of the spray. Bifenthrin was more effective over the longer term, but IC2 appears to be an effective, minimum-risk alternative to synthetic compounds as an acaracide in the fight against Lyme disease vectors.
There is currently little in the way of evidence supporting the use of B1 (thiamine), or garlic as insect repellents, but certain compounds found in essential oils have been found to have repellent qualities. Alpha-pinene, limonene, citronellol, citronellal, camphor and thymol are all thought effective against arthropod and insect vectors, although specific tick-tests remain absent. Popular alternative insect repellents such as neem have given highly contradictory results in testing and are not currently recommended by the CDC or other agencies as effective tick control. There is some evidence that soybean oil and coconut oil are effective against mosquitoes but not to the same degree as DEET (Maia and Moore, 2011).
Have You Been Poisoned by Deet?
Whichever method is used for Lyme disease prevention, insecticides, acaracides, and pesticides all require careful adherence to their usage guidelines. Those who think that they or their children may be suffering from adverse effects of DEET, permethrin, or another tick-repellent should contact their local poison control center immediately. Extra information on active ingredients in insect repellents is available at the National Pesticide Information Center (NPIC) at 1-800-858-7378 from 8:30 a.m. to 6:30 p.m. (Central time) seven days a week, excluding holidays. It is important that any adverse effects from tick-repellents, and other products are reported, not only so that patients can receive necessary medical treatment but also so that more information is available on the safety of DEET and permethrin, amongst other products.
Rand PW, Lacombe EH, Elias SP, Lubelczyk CB, St Amand T, Smith RP Jr., Trial of a minimal-risk botanical compound to control the vector tick of Lyme disease. J Med Entomol. 2010 Jul;47(4):695-8.
Nerio LS, Olivero-Verbel J, Stashenko E., Repellent activity of essential oils: a review. Bioresour Technol. 2010 Jan;101(1):372-8. Epub 2009 Sep 2.
Maia MF, Moore SJ., Plant-based insect repellents: a review of their efficacy, development and testing. Malar J. 2011 Mar 15;10 Suppl 1:S11.