Friday, 10 June 2011

What is the best Poison?

"What is the best poison to buy?"

This is another of those frequently asked questions.

Well, lets just start by getting the terminology right.

We use 'rodenticides' to control rodents. It sounds pedantic, but there is a difference. A rodenticide is usually a ready to use product, which is formulated using a base material (most commonly cereal) and an active ingreadient (the 'poison' part, if you like).

There are lots of myths about rodenticides. The usual myth is that professional pest controllers have access to pesticides that are not available to the general public. This is only part myth (unfortunately), as most of the rodenticide formulations used by professionals are also on open sale in DIY stores and agricultural merchants (albeit with different brand names).

So why use a professional pest controller?

Well, as I often tell people; "it's not what you use, but how you use it".

The simple fact is that when people fail to control rodents, it's usually down to the operator; not the bait. People use the wrong formulation, and place the bait in the wrong places, sometimes risking wildlife in the process.

To understand the best ways of getting control, you need to know about two things.

The first thing is the rodents. Lets concentrate on rats for a start, as they are the most likely target. This isn't going to be a biology lesson; yes, it helps to be able to identify the animal you intend controlling, but I'm not about to get into that here. There are a few basic facts about rat behaviour that help when controlling them.

Rats are 'Neophobic' - That means that if you introduce anything new into their territory they will actively avoid it until they are sure it is safe. So when you put a plastic bait box, or even a tray of food down, they won't eat it straight away.

Rats are 'gorgers and hoarders' - When rats find a food source they like (and feel safe with), they will eat as much as they safely can and then try and carry the rest away for consumption at a later date. That means that if you put too much bait down, the chances are that they will take some away, and store it somewhere where your pets or wildlife may be able to get it.

And what about bait?

Rodenticides come in various formulations, but the only active ingreadients available in the UK today are anti-coagulants.

Anti-coagulants work by replacing an enzyme in the blood that causes clotting. Effectively, they cause death by hemmorage.

The beauty of anti-coagulants is that they are very safe to use. They are safe to use because they build up gradually in the body, and have a delayed effect. This is very important, because without that delay, the rats may not consume a lethal dose, and could become 'tollerant' to the active. It also means that should the worst happen, and something which you don't want to die eats bait, it is possible to administer an antidote.

Currently, there are four active ingreadients commonly used in the UK. They are:

Difenacoum - For use indoors and outdoors.
Bromadialone - For use indoors and outdoors.
Floucoumafen -For use INDOORS ONLY
Brodifacoum - For use INDOORS ONLY

There are some other less common actives, like Warfarin that are still available, but the average DIYer isn't likely to see them.

Several different formulations are also available, inluding (but not limited to):

Whole Wheat
Cut Wheat
Rolled Oats
Pressed Cereal Blocks
Wax Blocks

Baits also contain an additional ingreadient which acts as a 'bittering' agent. Rodents can't taste it; but it is so bitter that it makes it nigh on impossible for a human to swallow the product.

So what is the best bait to use? Well, there isn't one. A professional should be able to choose a suitable active ingreadient, and the most appropriate formulation. My most common choice is either Difenacoum or Bromadialone on whole wheat for rats, or paste for mice.

Here are some basics for DIY control:

1. Always read the product label!
Even if you've bought the product before, READ THE BLOODY LABEL! Why? Well, because it tells you how to use the product! Labels change, and failure to adhere to the statuatory conditions of use is a criminal offence.

2. Make sure it's only rats that can get at the bait

You would be amazed at some of the places I've seen bait put down. The fact that it's called 'Rat Bait' doesn't mean that birds won't eat it! Bait needs to be placed somewhere where rats can get at it, but other animals can't. Sounds simple doesn't it....

3. Put down the amount the label says
No more, no less. There needs to be enough for the bait to have an effect, but not so much that the rats have a feed and then carry off the rest. The label will tell you how much to place down, and don't ignore what it says.

4. Don't expect an instant result
See above. The baits have a delayed effect. It can take up to a week for a rat to actually expire after it's eaten a lethal dose.

5. Keep checking the bait
Anti-coagulants work on a cumulative basis. The lethal dose builds up over a period of time, and it's important that once the rats have found the bait, they don't run out. Check it every day (don't forget the neophobia; it may take a few days to start with), and keep it topped up. DON'T be tempted to put extra down; remember that you should only ever have the amount recommended on the label.

6. Check for dead bodies
Every day, when you check the bait have a good look around for signs of fresh activity and dead bodies. Dispose of any dead rodents in your domestic waste.

7. Pick up the bait at the end of the treatment
Don't leave bait down all the time 'just in case'. Once the bait take stops, remove the bait and dispose of it. Keeping bait down all the time may seem like a good idea, but actually it's a very bad thing to do. You will kill lots of non-target species (like field mice) that could be food for other animals that you don't want to harm. There is also the possiblity that rats may not have a full dose available and therefore become tollerant to that active ingreadient.

8. Wear gloves AND wash your hands
Rats carry and spread lots of very nasty things that KILL. Everywhere they go, they spread these nasties, and you need to make sure you don't catch OR spread anything yourself. Wash your hands with a good quality antibacterial soap, and if you have kids, teach them the same routine.

9. Try and change things
You've got rats for a reason. Try and change things to stop the problem happening again. Have a read of my previous post.

I make no apology for this. It cannot be stresed enough; instructions are put on the label for a reason. No matter how much experience you have, or how good you think you are, please, please, read the label.

Still got problems?

Well, if you need to bait for more than a few weeks then there is something wrong. Get in a professional because you may have rodenticide resistance or something else.

You can contact us on 0800 812 8430 or for customers outside our trading area, choose a member of the NPTA or BPCA (all the others are just logos).

We are also happy to offer free help and advice via email.

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