Smells Good, Lasts Short Time

Wednesday February 14, 2007


Mr Pest Control


I have a question about XT-2000 Orange Oil. About how long does it last in wood after a treatment? I've heard it's only about 4-8 days and then the wood is edible again. Do you have any info on this? Thanks.

Mr Pest Control


My knee-jerk opinion was that the active ingredient - d-limonene, or orange oil - essentially has no residual, but I decided I should be fair about it and look around awhile. I feel vindicated after reading a few websites that seemed to know what they were talking about (because they agreed with me). One private pest control company website stated as you did that the residual was no more than 4 days, after which there would be no effect on termites walking on or chewing through treated wood. The second website was a tutorial from University of Illinois, in which the authors state that d-limonene has NO residual value, evaporating quickly from the surface. Now, these statements do conflict with others that I find that state the oil is absorbed into the wood and is effective for up to 1 year whenever a termite attempts to eat the wood. However, I am inclined to believe that it is meant as a contact insecticide only, affecting termites that are directly treated or that walk on the treated surface while the oil is still fresh and damp.

There are several products with d-limonene for drywood termite control, including the XT-2000 and Orange Guard, and there is no disputing their effectiveness within the boundaries of their true capabilities. One thing that does get to me though, is the sales pitch given by far too many outlets trying to sell various d-limonene products to homeowners. You can browse the internet and time and again see the statements "totally non-toxic and safe" for use around people and pets. You and I and the rest of our heavily regulated industry know very well that if we spoke these words we'd quickly have our regulators leap onto us and pummel us senseless. A pathetic program was undertaken in California a few years back by an anti-pesticide group that labeled themselves "public watchdogs", in which they browsed yellow pages ads and promptly sued any pest control company that dared to even hint at low risk pest management, including suing companies for using the words "safely" and "healthy" in their ads. They sued companies for putting depictions of children in their ads, all of which boiled down to a fund-raiser on the part of this group.

The fact is that d-limonene IS toxic, and its LD-50 is 4,400 mg/kg, just about the same as many of our pyrethroid termiticides. The product labels carry the signal word CAUTION, and warn of the need for immediate medical attention should the product be swallowed, immediate washing of skin if contacted, and possible severe irritation to eyes or lungs if exposed in those ways. In lab studies high doses caused a variety of problems to mice, and high doses applied to cats caused tremors, salivation, muscle weakness, and other problems. We need to look past the retail rhetoric and recognize that all insecticides are toxic, and all must be used with care and according to label directions. The real losers will be homeowners who buy into the hype given by the retailer they purchase the product from, and figure "hey, it's not toxic....don't have to follow directions".

So, there's my soap box and I'm stickin' to it, but hopefully our licensed, professional, trained industry already knows it. This plant-derived orange oil insecticide is a great option to have available for our pest management programs, and there will be those people who prefer to have Natural pesticide products applied in their home. However, we need to know enough about the chemistry to be able to tell them what to expect from the treatment, and to suggest that orange oil lasts a long time does not appear to be accurate.

Mr. Pest Control

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Please note, Mr. Pest Control is answering questions supplied by PMP customers across North America. His answers are generated from industry and manufacturer-provided information. The answer may not be specific to the laws and regulations for your State, Province, Territory or Country. In addition, products mentioned may not be registered and or available in all areas. Always check with your local Univar office for specific information to your area. Always read and follow label directions.