Yes, orange oil kills termites. Few pest control experts would dispute this basic claim. But ask the more loaded question, Does orange oil really work for termites? and you'll likely get a lot of differing opinions. One reason is that the question may be less about the efficacy of orange oil and more about the debate over methods: local (or "spot") treatment vs. whole-house (typically fumigation) treatment. Orange oil is a spot treatment, with the same advantages and disadvantages as any local treatment.

What Is Orange Oil?

Orange oil is an extract of orange rinds used in many products, including natural cleaning solutions and even food additives. The active ingredient in orange oil-based termite treatments is D-limonene. Different treatment solutions carry different levels, from as little as 10% up to 95%. Orange oil kills termites by breaking down their exoskeletons and destroying their eggs. There is some evidence that orange oil fumigation (exposure to air in treated areas) helps kill termites, but direct contact is much more reliable. While orange oil is considered a low-toxicity treatment, it is not harmless; it should not be ingested, and exposure to the oil or strong fumes can irritate the skin and eyes. Those with allergy sensitivities may experience lung irritation and other symptoms with exposure.

NOTE: Orange oil is designed to treat for drywood termites; it is not effective against subterranean termites.

Orange Oil Application

Pest control pros apply orange oil treatments by injecting the liquid treatment through holes they've drilled in affected wood and other building elements. Ideally, the oil is injected directly into the galleries (hollowed-out channels where termites live inside the host material). Finding the infestation sites and galleries is the tricky part. Pros may use a variety of methods to locate termite presence -- everything from borescopes (little cameras) to audio detection to termite-sniffing dogs -- in addition to good old-fashioned sight inspections. The holes for injecting oil are pretty small, but they may be required every 5 inches or so in an affected area, leaving a lot of patchwork following the treatment. On the upside, you don't have to vacate your home, double-bag your food or turn your house into a circus tent, as you do with fumigation treatments.

Does Orange Oil Work As Well for Termites?

The primary point of debate between orange oil (and other local treatments) and fumigation (and other whole-house treatments, such as heat) is access. With local treatments, you have to find the termites to eradicate them. With fumigation, the entire house is treated at once and the treatment (typically a gas) penetrates all walls, floors and other surfaces, including the solid lumber where the termites most likely reside. So if the question is, Does orange oil work for termites as well as fumigation? the answer, arguably, is No, simply because fumigation provides a better guarantee that all infestations will be treated. With local treatment, if the pest control operator fails to detect an area of termite activity, it's left untreated. Both orange oil and standard fumigation methods are non-residual, meaning that once the treatment material has dissipated, there's no residual material left to prevent termites from returning.

Orange You Glad You Asked an Expert?

There's plenty of evidence to confirm that orange oil does indeed work for termites, but it also has clear limitations. The best way to learn more about orange oil treatment and whether it's suitable for your situation: consult local pest control professionals. You might also talk with a local extension office for more -- possibly less biased -- information on termite threats and treatments in your area. In general, termite control of any kind is not recommended for DIYers, so avoid the temptation to rush out and buy some orange oil with the confidence that you can't do much harm with a low-toxicity treatment. You probably won't do much harm, but the termites you miss definitely will.

Philip Schmidt writes for Networx.com.

Updated January 21, 2018.