Interpreting Pyrethroid Labeling

Wednesday July 4, 2012


Mr Pest Control


I first want to say that I am enjoying the updates to the Master Technician series. Thank you for your vigilance in making this a current resource. Next, my question. With the change in the labeling for synthetic pyrethroids I need to confirm or maybe update my understanding of spot treatments. I have a long history in the industry and in the past I believe it was acceptable to string spot applications side-by-side together, relying on an accepted not-to-exceed percentage of a given surface of the application. At this point, I have a concern with the validity of the spot treatment percentage issue and the demands of the new labeling. Specifically, the limitations for use around the exterior of the home at windows and doorways. My question is this: Is it currently considered a compliant application if spot treatments are attached side-by-side as long as the areas of the spots combined does not exceed a certain percentage of the given surface? Thank you for your input on this concern.

Mr Pest Control


Good morning Eddie, and thank you for the compliments. I see you are in Colorado, so I hope you and your home are safe from the awful fires. 

We discussed this "spot" treatment definition in the past, and you and I have the same memory that there was always a limitation on how much of the overall area could be covered with "spots". The EPA definition of a spot is quite clear - "no individual spot may exceed 2 square feet". However, with this new pyrethroid labeling I spent quite awhile trying to find out if there was any more to this, and apparently there is not. The dimension of that "spot" are not defined, so I suppose it could be a spot 1 foot wide by 2 feet long, or 6 inches wide by 4 feet long, or to be silly about it a spot 2 inches wide and 12 feet long - all of these add up to 288 square inches, which is 2 square feet. We should use good common sense on this part. 

But, the EPA does not state anything further, so our memory of being told that we could cover "no more than 20%" of an overall surface with spots seems to have been fabricated by someone. However, I have seen, on a couple of product labels, the instruction that no more than a specific percentage of the overall surface could be covered by spots, so for those specific products the label must be followed, and this emphasizes why it is so important to carefully read every word on every product label before we use it. I have talked with state regulators, NPMP specialists, and they have talked with EPA, and the consensus seems to be that there is no mention of how close together we can place the spots or how much of the overall surface can be covered with spots.

So, this unfortunate vagueness leads to problems, because now everyone has the liberty of making their own decision, which probably is not in the spirit of this whole issue and the requirement to place only small spots of pesticide on any surface. I suppose that legally it could be as you suggest, that as long as you interrupt the application of the spray after every 2 square feet is covered you could just put all the spots adjacent and end to end, ultimately ending up with the whole surface covered. Clearly this is not in the spirit of the law on spot treatments, but would just be taking advantage of, perhaps, an oversight by the EPA on this definition (which, by the way, is DECADES old). 

For this reason I always encourage technicians to open a dialogue with their local regulatory agency, and ask those folks exactly how THEY interpret this law in their jurisdiction. They may have a very concise opinion that you must follow. With respect to the new pyrethroid labeling and treatments around doors and windows, the EPA did work with California's CDPR to state that the application of a "pin stream" around doors and windows, where no true crack or crevice exists, would be defined as a surface treatment with a 1 inch wide band, and that this would be in compliance with the new labeling. EPA states that this kind of treatment would fall within their "exceptions" for either C&C or Spot treatments. 

So, in summary, EPA at this time does NOT address how much overall surface can be treated with spots, but does clearly define a "spot". Good common sense by our industry has to come into play as well as working with local regulators. All of the updated Pyrethroids information is on PestWeb in our "Industry / PestWeb Features" resource. Nice to talk with you Eddie. 

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.