A naturally-occurring compound prepared from pine oil that seems to deter mosquito biting and repels two kinds of ticks has been found by Agricultural Research Service (ARS) scientists.

A patent (US 7,378,557 B1) was issued on May 27 for the compound, isolongifolenone, and partners are being sought to bring this technology to commercial production.

In laboratory tests, ARS chemist Aijun Zhang in the Invasive Insect Biocontrol and Behavior Laboratory, Beltsville, Md., and his colleagues discovered that the naturally occurring compound deters the biting of mosquitoes more effectively than the widely used synthetic chemical repellent DEET. The compound also repelled two kinds of ticks as effectively as DEET.

Insect repellents are used widely to prevent bites from mosquitoes, sand flies, ticks and other arthropods. For the most part, people apply repellents just to avoid discomfort, but there is a more serious side to the use of these products. Human diseases caused by blood-feeding ticks and mosquitoes represent a serious threat to public health worldwide.

Malaria is the chief threat, killing approximately two million people per year and threatening billions. Other diseases include dengue fever, chikungunya, Lyme disease and typhus. Some segments of the public perceive efficient synthetic active ingredients as somehow more dangerous than botanical compounds, giving additional importance to the discovery of plant-based isolongifolenone.

Zhang's team also developed an easy and efficient method to prepare this repellent. Many natural-product chemicals isolated from plants and essential oils have proven to have repellent effects. Most often, such compounds never attain commercial development and their use is limited or impractical because they are expensive and not available in pure and large quantities.

In contrast, this newly-discovered repellent can be prepared inexpensively from pine oil feedstock in ton quantities for large-scale commercial applications, giving it a significant advantage over many of the other natural-product repellent chemicals.

ARS is a scientific research agency of the U.S. Department of Agriculture.