Pyrethroid Interpretations

Monday August 6, 2012


Mr Pest Control


Here's something that I don't understand. We can no longer apply Talstar EZ granules in the rain or when rain is forecasted within the next 24 hrs due to the new "synthetic pyrethroid laws". This makes no sense to me as this is a water-activated product. Also, due to the new "labeling", we are not allowed to apply these products above 3 feet and only as spot treatments. So here's my question: What can I use to treat around the eaves of houses / buildings that have a problem with spiders? Pyrethroids such as Cyfluthrin, Beta-Cyfluthrin, and Cypermethrin have been the only products that I have had significant results with on spiders. (Cypermethrin being the best)

Mr Pest Control


While my thoughts on this are likely not to be entirely satisfying, hopefully they will be somewhat helpful in clearing up the new requirements. The whole issue of the new label restrictions is to minimize as much as possible the opportunity for the pyrethroid active ingredients to find their way OFF the treated site and into local waterways, most likely via the gutter and storm drains. The blanket requirement for all pyrethroids now, regardless of the formulation, that they not be applied during a rain event could seem unnecessary when you are applying it for labeled pests where the Label then requires that you water over the treated area anyhow. Gosh, why not let that rain do the job for you?

I suppose it was the concern that if the applicator is given the ability to decide for himself when it was okay to apply in the rain and when it would be a runoff problem some bad decisions would be made. Rather than leave it up to the judgment of the applicator the EPA simply made one single statement - "Do not make applications during rain". I agree that this seems foolish when you are required to water over the granules anyhow, but that is what we have to live with at this time. Perhaps it is because you have no way of knowing how MUCH rainfall will occur, and since the Labels require, more or less, specific quantities of water to move the a.i. into the soil or thatch, it is preferred that the applicator do the watering to stay within the Label recommendations. I don't like the word "activate" myself, and on the Talstar EZ label it does follow that word with the clarification that the water is used to "release" the a.i. from the granule carrier. 

With respect to treatments around the structures let's clarify some things as well. Up to 3 feet "above grade" (the soil, the walkway, etc.) you can apply the material as an overall application. It is above 3 feet that you are restricted to crack and crevice or spot applications. You might check with your own local regulatory folks on this too, as some states wanted to restrict it to a height of only 2 feet, and the EPA does allow states to be more restrictive than the federal regulations. But, with respect to treating the eaves, the EPA was asked about this specifically, and their response was that they considered the surface directly on the underside of the eaves to be a treatment that falls within their exceptions to the requirement for either spot or crack and crevice only. Again, I am always happiest when you discuss these kinds of interpretations with your own local regulatory agency, as they will be the ones who have the final yea or nay on this. 

If they agree with what I believe the EPA allows on this, then you could continue to treat the under-surface of the eaves, where protected above by the roof, as an overall application. However, even if they disagree with me keep in mind that a "spot" treatment is 2 square feet, so a 1 foot by 2 foot swath of spray or any other dimension that equals 288 square inches. This definitely should be sufficient to treat the critical points under the eaves, particularly since EPA does NOT state how far apart those "spots" need to be. But, use good judgment on this. 

I myself have not yet found another spray-on insecticide that is not a pyrethroid that has the same broad outdoor uses that many pyrethroids did. Some of the non-pyrethroids seem to come close but in my opinion stop short of allowing overall treatments of exterior walls, for example, for carpenter bees or over-wintering pests. The NPMA currently is working with EPA to try to get some additional exceptions for certain serious structural pests, such as stinkbugs and others that invade during the winter. 

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.