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A Little Dab Will Do Them........In

Thursday August 9, 2012

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Mr Pest Control

Question:

How many ounces or grams makes a lethal dose for rats using Talon G?

randall, CA

Mr Pest Control

Answer:

When Talon (brodifacoum) first came on the market as the first single feeding anticoagulant rodenticide we were told by the manufacturer that a single pellet was sufficient to kill a house mouse and 3 pellets could kill a typical rat. Clearly this is not much bait, attesting to the higher toxicity of the active ingredient. In fact the LD-50 of pure brodifacoum to a Norway Rat is 0.27 mg/kg, compared with warfarin (58 mg/kg) or diphacinone (3.0 mg/kg). I took these numbers from a resource by Cornell University. 


Now, we never offer PURE active ingredient to rodents, but it is greatly diluted with food ingredients, paraffin, etc., so the end result according to this resource is that it takes a lot more of the bait to kill that rodent. So, here are some relative amounts for typical warfarin, diphacinone, and brodifacoum bait products to be the lethal dose for a rat, and presumably a Norway Rat since these are lab results. 

Warfarin bait of 0.025% - LD-50 is 58 grams of bait, or nearly 2 ounces.
Diphacinone bait of 0.005% - LD-50 is 11.5 grams or just over 1/3 ounce.
Brodifacoum bait of 0.005% - LD-50 is only 1.4 grams, or about 1/14 of an ounce. 

As you can see, brodifacoum takes just a very small amount to reach that lethal dose. Since this in general is based on the weight of the animal eating the toxicant a much larger animal like a dog would have to consume a correspondingly much larger amount of the bait to reach a presumed lethal dose. According to one of our industry's top rodent control experts the likelihood of this kind of "secondary" poisoning, from a dog eating enough rats to consume the lethal dose, is highly unlikely. But, since the remote possibility still exists it is important to adhere to the label requirement on most rodent bait products that all dead or dying rodents be removed and disposed of quickly after a baiting program is begun. 

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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.

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