Insect Repellents

When you head for the woods or the desert, do not forget the bug spray. Mosquitoes, ticks and flies can take a lot of the fun out of prospecting. Plan ahead and avoid the irritation. 

Insect Repellents Cooperative Extension, College of Agriculture & Life Sciences,  The University of Arizona

Written by  Dawn H. Gouge, Assistant Specialist, Entomology Carl Olson, Associate Curator, Insects Kirk A. Smith,Assistant Research Scientist   Introduction Choosing Insect Repellents Using Insect Repellents Safely Important Information on Using Repellents Types of Repellents Chemical DEET IR3535-based repellent Botanicals Citronella or Lavender Oil Eucalyptus oil Soyabean oil Mineral oil Permethrin Reference Introduction Mosquitoes, biting flies, chiggers and ticks can be annoying and sometimes pose a serious risk to public health. In certain areas of the United States, mosquitoes can transmit diseases like equine and St. Louis encephalitis. More recently transmission of West Nile Virus has become a major concern. Biting flies can inflict a painful bite that can persist for days, swell, and become infected. Ticks can transmit serious diseases like Lyme disease (the north western corner of Arizona is classed as a low risk area, it is only in this part of Arizona that the vector exists at all) and Rocky Mountain spotted fever. When properly used, arthropod (insects, ticks, mites, etc.) repellents can discourage biting arthropods from landing on treated skin or clothing. Choosing Insect Repellents Insect repellents are available in various forms and concentrations. Aerosol and pump-spray products are intended for skin applications as well as for treating clothing. Liquid, cream, lotion, spray, and stick products enable direct skin application. Products with a low concentration of active ingredient may be appropriate for situations where exposure to insects is minimal. Higher concentration of active ingredient may be useful in highly infested areas or with insect species which are more difficult to repel. Where appropriate, consider non-chemical ways to deter biting insects — window and door screens, bed netting, long sleeves, and long pants.   Browndogtick Tabanus Using Insect Repellents Safely The Environmental Protection Agency (EPA) recommends the following precautions when using insect repellents: Apply repellents only to exposed skin and/or clothing (as directed on the product label). Do not use under clothing. Never use repellents over cuts, wounds, or irritated skin. Do not apply to eyes and mouth, and apply sparingly around ears. When using sprays do not spray directly onto face; spray on hands first and then apply to face. Do not allow children to handle the products, and do not apply to children’s hands. When using on children, apply to your own hands and then put it on the child. Do not spray in enclosed areas. Avoid breathing a repellent spray, and do not use it near food. Use just enough repellent to cover exposed skin and/or clothing. Heavy application and saturation is generally unnecessary for effectiveness; if biting insects do not respond to a thin film of repellent, then apply a bit more. After returning indoors, wash treated skin with soap and water or bathe. This is particularly important when repellents are used repeatedly in a day or on consecutive days. Also, wash treated clothing before wearing it again. If you suspect that you or your child are reacting to an insect repellent, discontinue use, wash treated skin, and then call your local poison control center if symptoms persist. If you go to a doctor, take the repellent with you. Reactions to repellents usually take the form of burning or irritated skin where the repellent has been applied. Get specific medical information about the active ingredients in repellents and other pesticides by calling the National Pesticide Information Center (NPIC) at 1-800-858-7378. NPIC operates from 6:30 a.m. to 4:30 p.m. (Pacific Time), 9:30 a.m. to 7:30 p.m. (Eastern Time), 7 days a week. The NPIC Web site is:http://npic.orst.edu/ Important Information on Using Repellents EPA recommends the following precautions when using an insect repellent: Check the container to ensure that the product bears an EPA-approved label and registration number. Never use a product that has not been approved for use by EPA! Read the entire label before using a pesticide. Even if you have used it before, read the label again - don’t trust your memory. Follow use directions carefully, use only the amount directed, at the time and under the conditions specified, and for the purpose listed. For example, if you need a tick repellent, make sure that the product label lists this use. If ticks are not listed, the product may not be formulated for that use. Store repellants away from children’s reach, in a locked utility cabinet. Types of Repellents  CHEMICAL   DEET  DEET (chemical name, N,N-diethyl-meta-toluamide) is the active ingredient in many insect repellent products. DEET’s most significant benefit is its ability to repel potentially disease-carrying insects and ticks. Products containing DEET currently are available to the public in a variety of liquids, lotions, sprays, and impregnated materials (e.g., wrist bands). Formulations registered for direct application to human skin contain from 4 to 100% DEET. DEET is designed for direct application to human skin to repel insects, rather than kill them. After it was developed by the U.S. Army in 1946, DEET was registered for use by the general public in 1957. Approximately 230 products containing DEET are currently registered with EPA by about 70 different companies. Skin sensitivity to DEET can develop after repeated use. EPA is no longer allowing child safety claims on product labels. These claims currently appear on certain products containing a DEET concentration of 15% or less. Use lower levels (<6%) of DEET on children and apply to clothing not onto skin. Do not use DEET on infants or if you are pregnant. Amount DEET Approx. Hours of Protection 30% 6.5 15% 5 10% 3 5% 2   Off Deep Woods  (SC Johnson) 23.8% DEET  301.5 minutes of protection time Off Skintastic for Kids  (SC Johnson) 4.75% DEET  88.4 minutes of protection time IR3535-based repellent A chemical repellent that has been used in Europe for over 20 years, IR3535 was approved for use in the United States in 1999.   Skin So Soft Bug Guard  (Avon) IR3535 22.9 minutes protection time   BOTANICALS Citronella or Lavender Oil   It is recommended that personal insect repellents such as citronella and oil of lavender not be used on children under 2 years of age. Registered citronella oil repellents protect people against mosquito bites for less than one hour. The registered lavender oil repellent protects for half an hour or less. The citronella-based repellents tested protected for 20 minutes or less. Slow release products do not provide significant added benefit. Based on animal studies, citronella-based products appear to be potential dermal sensitizers. Therefore, allergic reactions may occur in some individuals . Eucalyptus oil Products containing eucalyptus oil were the most effective herbal repellents tested and lasted as long as low concentrations of DEET!!   Repel Lemon Eucalyptus Insect Repellent  (WPC Brands)  120.1 minutes protection time Fite Bite Plant-Based Insect Repellent  (Travel Medicine) 120.1 minutes protection time   Soyabean oil   Bite Blocker for Kids  (HOMS)  soybean oil  94.6 minutes protection time   Mineral oil   Skin-So-Soft Bath Oil  (Avon) 9.6 minutes of protection   Permethrin As a treatment for clothing only. Use by itself or with skin applied repellents. Permethrin is a contact insecticide. That is, it kills ticks or other insects when it comes in contact with them. It is used on clothing and materials only. It uses the same active ingredient used in hair shampoos for head lice. Skin contact should be avoided and deactivates Permethrin within fifteen minutes. As a clothing, tent or sleeping bag application, Permethrin is very effective at keeping ticks from attaching to you and at reducing mosquito bites. Permethrin is an effective repellent against mosquitoes and flies and can be used in conjunction with a skin based repellent. Spray applications of Permethrin can remain effective up to 14 days of exposure to light or oxygen, or through two aggressive washings. By storing the treated clothing in black plastic bags between uses the fourteen days of protection can be extended considerably. If necessary a heavier application can remain effective even longer. Bed nets can be treated with permethrin. Reference Product data has been taken from: Fradin MF, Day JF. Comparative efficacy of insect repellents against mosquito bites. New England Journal of Medicine. 2002. 4;347(1):13-8. Triatoma protracta dorsal Triatoma protracta ventral Triatoma recurua dorsal Triatoma recurua dorsal Triatoma rubida dorsal Triatoma rubida ventral