Using Orange Oil to Treat Drywood Termites

A close-up of termites in wood
Bryan Mullennix/The Image Bank/Getty Images

Although orange peel shavings can be used to flavor foods, and small doses of the oil from the orange peel is said to convey health benefits, large amounts of the oil can cause vomiting and nausea. Such negative effects are even greater when the orange oil is used against insect pests, as it can be deadly to a number of insects, such as cockroaches, ants, dust mites, flies, wasps, spiders, crickets and of course termites

What Is Orange Oil?

Although orange oil smells strongly of oranges, it is not orange juice, but an extract from orange peels that is insoluble in water. Not only would drinking a cocktail of it would cause severe stomach upset, but a spill can be very irritating to the eyes and the skin.

Some people even suffer severe allergic reactions upon exposure to orange oil. So, as always, caution is advised not only for the applicator of orange oil but for those who will occupy the structure after treatment.

Orange Oil as a Termiticide

In the 1930s, California researchers began injecting arsenic into active infestations of drywood termites, finding that the termites not killed by the initial application usually succumbed to toxic residues. Now 80 years later, a natural product, orange oil, is being marketed as a herbicide and insecticide, with particular kudos to its effectiveness against dry wood termites. So, what is this wonder product and how does it kill termites?

How Does Orange Oil Kill Termites?

The active ingredient of orange oil is D-Limonene, a chemical known to be an effective insecticide against a variety of pests from flies, to mosquitoes, ants, crickets, and mites. Scientists say that the oil dissolves the termite's exoskeleton, destroying the insect's cell membranes and triggering a lethal chain of events that ends with the bug dying from massive losses of water and protein.

Inspect, Inject and Inspect Again

The mode of treatment once a drywood colony has been found by canines or humans is to drill holes into the infested wood and to inject the orange oil into the hollow spaces where the termites are feeding. Studies show varying amounts of residual effects from three days to three weeks.

The majority of termites are killed by direct contact, and since orange oil deters the termites from feeding, some of them will starve. After the treatment, the home or business owner should periodically check for signs of new infestation. Trained termite-sniffing dogs have been very effective in sniffing out new or previously undetected termite colonies.

The Future of Orange Oil

The jury is still out on orange oil being a do-all, end-all termite treatment, with some university researchers remaining skeptical about its efficacy, such as those of the Agriculture and Natural Resources, University of California which stated, "There are many localized [drywood termite] treatment methods available that include both chemical and nonchemical options. ... Botanical-based products (e.g., orange oil and neem oil) have been tried, but recent lab and field tests from two universities question the efficacy of at least d-limonene.

Although there does seem to be some controversy about the effectiveness of orange oil, there are users who are seeing some success with treatments, so the natural pesticide is certainly worthy of consideration as a least-toxic termite management option.