Nov 6, 2012 – Fact or Fiction, Effective or Failure?


I was asked today about using cotton balls in a bowl of bleach to keep squirrels away? I told this customer I had never heard that before. It sounds like a tall tale but I don't know much about it. What do you know?


This is fun. The internet provides such a wealth of bad information that homeowners can go to, that I suspect this customer picked this one up at some website offering home remedies to keep squirrels away. First, though, let's examine the legality of this with respect to the involvement of a pest management professional. The EPA defines a "pesticide" as any substance that prevents, destroys, repels, or mitigates in any way any pest. The word "repels" is very important there, as the use of substances like mint oil, garlic oil, moth balls, or bleach to repel animals would be to use them as "pesticides", and nearly all pesticides must be registered for that use by EPA. Now, there are certain "exempt" active ingredients that can forego EPA registration, but they still need to be properly labeled for this kind of use in pest management. 

Thus, we as PMP's are obligated to use products properly labeled for that use, and I would go further to suggest that we AVOID making what would be taken as a recommendation for a homeowner to use these concoctions as well. In a case like this, if I open the door to all possibilities, if you agree with this customer that sure, what the heck, bleach might work really well to annoy squirrels enough to make them go away, you have put your stamp of approval on this use. Now the homeowner puts out a big bowl of bleach with a pile of cotton balls in it and their dog eats them and dies. Guess who is to blame for the death of the dog? really does pay to tread lightly around issues like this and stick to what we know is tried, true, and legal. 

In this case I don't know where this homeowner would want to put that bleach, but perhaps it's in the attic for tree squirrels or maybe on the ground under a bird feeder or just someplace around the fence line. Presumably bleach (or moth balls or other oils) would repel by creating a strong enough odor that the animals don't like it, and if it is that strong it could also be harmful to pets and people. By the way, if you want to scare the beejeebies out of people show them the MSDS for good old 5% household bleach. If we had a pesticide with that horrific of wording we'd never use it. The LD-50 in rats is 5800 mg/kg, making it MUCH more toxic than the diluted insecticides we apply within structures. 

But, people are always looking for something other than "toxic pesticides" to use to kill or repel their unwanted bugs and rodents, so they look to household materials that they feel comfortable with, or use plant based chemicals and other "natural" chemicals that they have been convinced are not toxic to humans. How could they be toxic? They're from plants. You know, from plants, like strychnine and nicotine. So, I suspect that many smelly materials would be repellent to squirrels but also to people. A major constituent of bleach is chlorine, and we know how irritating and painful chlorine can be when we inhale too much of it, so repelling rodents might require that excessive exposure too. 

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