06 February 2009

Stronger than DEET - new repellent from a tree

Blood-sucking insects terrify me more than sea snakes, stonefish and other so-called scary marine creatures. DEET is a great repellent, except that it is industrial strength insecticide and is toxic to marine life. So these are seldom used by us. We prefer to cover up and flee from sand flies and mossies when they are abundant.

Thus it's exciting to read about a source of new mosquito repellent as effective as DEET, but from the Tauroniro tree (Humiria balsamifera) of South America.

From the USDA Forest Service website, this tree is found in the Guianas, Colombia, Venezuela, and the Brazilian Amazon. In Guyana it is a principal dominant species in the marsh forests; does best on light sandy soils. In Surinam, it occurs in savanna forests.

Tropical forest tree is source of new mosquito repellent as effective as DEET
mongabay.com 5 Feb 09;
Isolongifolenone, a natural compound found in the Tauroniro tree (Humiria balsamifera) of South America, has been identified as an effective deterrent of mosquitoes and ticks, report researchers writing in the latest issue of Journal of Medical Entomology.

Derivatives of the compound have long been used as fragrances in cosmetics, perfumes, deodorants, and paper products, but new processing methods may make it as inexpensive to produce as DEET, a potent and widely available synthetic insect repellent that works by blocking the aroma of human sweat.

The authors, led by Aijun Zhang of the USDA's Invasive Insect Biocontrol and Behavior Laboratory, found that isolongifolenone deters the biting of the mosquitoes Aedes aegypti and Anopheles stephensi "more effectively than the widely used synthetic chemical repellent N,N-diethyl-3-methyl benzamide (DEET) in laboratory bioassays" and repels blacklegged ticks and lone star ticks "as effectively as DEET".

Since "isolongifolenone is easily synthesized from inexpensive turpentine oil feedstock," the authors write, "we are therefore confident that the compound has significant potential as an inexpensive and safe repellent for protection of large human populations against blood-feeding arthropods."

Tauroniro — which is also known as Bastard bulletwood, Oloroso, Couramira, or Turanira — is found in marshy forests in the Guianas, Colombia, Venezuela, and the Brazilian Amazon, according to the U.S. Forest Service.

A. Zhang et al. Isolongifolenone: A Novel Sesquiterpene Repellent of Ticks and Mosquitoes. Journal of Medical Entomology, Volume 46, Number 1, January 2009 , pp. 100-106(7)

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