On-going ads by some tout “Orange Oil” as “The Green” treatment alternative against termites.  So is orange oil a viable alternative or is it just another new marketing ploy painting the planet orange, green, blue or any other color of the rainbow with catchy ads? How does orange oil compare to other known and new treatments and is it truly effective and reliable?

History and Facts: The citrus industry produces many bi-products from concentrates to compounds used in foods, cosmetics, chemicals and other areas. The rind acid of citrus fruit is mechanically, steamed or chemically extracted to produce d-Limonene (C10H16 ), a hydrocarbon oil (terpene) also found in conifer and some other plants. The orange oil extract (OOE) is used as fragrance, solvents or dispersing agents found in various products from candles to paint stripper, cleaners, detergents, shampoo, sprays and some insecticides. Orange oil extracts are used mostly as mild repellents against fleas, mites and mosquitoes.

Orange Oil and Termite Treatment: Orange oil is a liquid that is pressure injected into the wood by drilling many 3/8″ holes into the wood in a V or X pattern every 2.5″ to 5″ apart. The key to using orange oil is getting enough product into the wood to absorb and travel through termite channels so it is critical to inject an ample amount. Orange is very acidic and will damage painted and varnished wall surfaces, wallpaper, fabric and other items, so it  is critical the technician performing the treamtent be very careful and cover furniture, flooring and wall coverrings. Orange oil has a smell that we like, but the termites don’t thorough treatment is or any surviging termites will move to other areas and avoid the treated wood. Since the orange oil evaporates and becomes less effective after it has dried, any exposed adjacent wood members should be treated with a borate material such as TimBor or BoraCare to provide a residual effect. Orange oil should not be used with non-repellent products like Termidor or Altriset which are engineered to be tasteless & ordorless. Using orange oil with Termidor and Altriset defeats the purpose of using a non-repellent product that termites won’t avoid. Orange oil is very acidic so caution is necessary to avoid skin, eye and mouth contact.

Effectiveness of orange oil: Lab test from UC Berkeley, UC Davis and UC Riverside’s Entomology Departments show that d-Limonene has a very short afterlife of only 2 to 3 days and lacks a residual effect to kill and prevent termites from reinfesting treated areas. Orange oil application does not work in soil treatment against Subterranean Termites, even as a repellent due to its short life. Additionally, it lacks the transfer effect from contaminated termites to pass on the toxicity of the product to other members of the colony and the termite queen who may survive and keep the colony alive. When applied directly to wood against Drywood Termites it is critical that a sufficient amount of oil reaches each and every termite or the colony will survive and continue feeding on wood members of the house. There is no current technology to know if all termites have been killed so companies who treat with orange oil also recommend application of another long lasting termiticide such as Tim-Bor or Bora-Care.

Comparison results of independant lab controlled tests from the universities and pest control professionals show that local orange oil treatment is less performant than Termidor-SC, Bora-Care or Tim-Bor, particularly over a long period of time.

SOURCE: Dr. Vernard Lewis, UC Berkeley & Dr. Michael Rust, UC Riverside

For additional information and details on the study and results visit the UC-Berkeley

* Altriset is the first and only registered termiticide without a warning label and classified as “reduced-risk” under the US EPA

Orange Oil vs. Fumigation:The Structural Pest Control Board of Californiastates that “orange oil is another localized treatment tool… against the elusive drywood termite. It is not an alternative to all-encompassing methods of treatment” such as fumigations (SPCB Newsletter). Like Termidor-SC, Bora-Care and Tim-Bor, orange oil treatments entails injection and/or surface treatment of infested wood members. Sulfuryl fluoride has been researched and effectively used for decades with very strict and controlled procedures and specific safety measures, all reviewed and supervised by the California Structural Pest Control Board, the Department of Pesticide Regulations and the Environment Protection Agency. Each year, thousands of structures (homes, apartments, schools, shopping malls, public buildings, silos, factories, railroad cars, etc.) are fumigated in the US and Canada when local treatments are not feasible. Fumigation does require vacating the structure, but it is a sure method of erradicating all drywood termites from the structure. Like orange oil, its greatest advantage is also its greatest weakness; no residual effect to prevent termites from re-infesting. For additional comparison between orange oil and fumigation treatments check: http://www.ywfumigation.com/images/vs.pdf .

Orange Oil vs. Termidor-SC and Other Termiticides: Like plant pyrethrins or synthetic pyrethroids, orange oil is another contact insecticide. The effectivness and smell last only 2 to 3 days and the treatment has no long lasting residual effect against remaining termites or to prevent termites from re-infesting treated areas. The challenge is to kill all termites on contact, including the queen or the colony will survive. This is very hard to do since the technician does not know where all colony members and the queen are located. Orange oil does not have a chemical transfer effect from one termite to another such as Termidor or Altriset (non-repellent) nor does it have any lasting effect such as as Termidor, Altriset, Bora-Care or Tim-Bor to contaminate other termites or keep termites from re-infesting treated areas. Given the analysis and results above and our experience of many treatments in wood frame homes, we prefer and recommend using Termidor-SC, Altriset, BoraCare or TimBor for a more effective and long lasting treatment.

Orange Oil & Health Hazards:Orange Oil may stain wall coverings and wood surfaces and should be applied carrefully. As a citrus bi-product, orange oil appears to be a green alternative. However its health hazard may not be limited to termites. The volatile citrus oil is a repellent to pets and can cause some humans and pets to experience allergies and some breathing difficulties, particularly among asthmatics and citrus allergic subjects with Pantothenic Acid (or Vitamin B-5) deficiency. Though it is labelled low toxicity, 92% pure d-limonene is still not approved for retail sale and results from renound organizations such as the IPCS and EPA indicate that, whether inhaled, oral or dermal, health hazards due to acute (high dose) or chronic (repeated) exposure do exist. Studies and analysis indicate that orange oil (d-limonene) should be handled like other low-toxicity insecticide (just like Tim-Bor, Bora-Care and Termidor-SC) and used with caution. In doubt, consult your doctor prior to any treatment and inform your pest operator of any allergies you may have to avoid any reactions. An alternative is to use odorless products such as Bora-Care, Tim-Bor or Termidor-SC.

Conclusion: In spite of its “green and eco-friendly” marketing appeal, orange oil  is not a reliable and absolute solution to completely erradicate all drywood termites. Its just another insecticide with its limitations for local treatments. But studies show that orange oil, even at high concentration, it is not as effective or long lasting as other commonly used termiticides at eliminating termite colonies, particularly in hidden and hard to reach areas. Some companies continue to promote orange oil because of its great ecological and marketing appeal but they use it in conjunction with other termiticides due to its limitations.

We have tried several orange oil applications and due to its low efficiency and lack of long term effectiveness, we have observed better local treatments results with Altriset, TimBor, Bora-Care andTermidor-SC without odors and without vacating your home. In addition to the effectiveness of the treatment, the thoroughness of the application and the quality of the work performed by the applicator is what matters and is most important to erradicate an infestation.