What is the proper, safe, and effective way to apply diatomaceous earth?

Question

We are looking at using diatomaceous earth against bed bugs.

However, we're having trouble finding any reliable information on how to use it properly.

Our questions are:

• how should it be applied?
• is it effective against bed bugs? How long does it take to kill them?
• where should it be put? Everywhere, or only in specific locations?
• how much should be applied?
• how often does it have to be reapplied, and does it have to be vacuumed up?
• after it's been applied, will a fan or wind disturb it and blow it into the air?
• is it safe to apply it on the outside of a bed (i.e. the sides of the mattress or on the sheets) and leave it there while sleeping?
• is it effective when wet? when the air is humid?

Answer 1

We have used DE effectively to kill bedbugs, so I'll take a shot

how should it be applied?

We applied it around the borders of all the floors, sprayed it into the walls everywhere we could (mainly into electrical boxes - remove the covers first), and into the underside of plush furniture. In the basement we put it all over the ceiling and walls as well as squirting it into every gap we could find.

is it effective against bed bugs? How long does it take to kill them?

Yes. They will avoid it if possible, so its tough to say how long it takes to kill them, but when we applied it to a heavily infested house and the improvement was immediate.

where should it be put? Everywhere, or only in specific locations?

Anywhere bedbugs can get.

how much should be applied?

A dusting around the perimeter of each room, a generous squirt of dust into openings and several squirts into plush furniture is what we did.

how often does it have to be reapplied, and does it have to be vacuumed up?

We only applied it once and that did the trick. If you vacuum it up it can't help, so no don't vacuum it up.

after it's been applied, will a fan or wind disturb it and blow it into the air?

Depends on the orientation and strength of the fan. A ceiling fan? No. A box fan pointing at a line of DE? Probably.

is it safe to apply it on a bed?

You should seal your mattresses up with bedbug preventing covers, and squirt the DE inside that. DE is harmless to you, but you want to trap the bugs in the mattress. Leave the mattresses sealed for at least 2 weeks or longer to ensure the bedbugs get exposed. They can hide and live for a long time in a mattress but a solid month should deal with the birth cycle.

is it effective when wet? when the air is humid?

No and not very.

Answer 2

I've done a lot of research and found answers to some of these questions:

• how much should be applied? According to this page, not much at all:

More is not better in the case of DE: bed bugs won’t walk through a thicker coating and so it won’t have a chance to kill them.

and

Do not use large quantities that are likely to be kicked up and inhaled, and do not place in windowsills where a breeze might blow the dust around.

and

What you want to do with DE is apply a light film. What I mean by that is a VERY LIGHT film. If you are applying it in a way that you are kicking up visible dust, you are putting WAY too much down.

---

• is it safe? There is more than one kind of diatomaceous earth, make sure that you're using food grade product -- this is the only kind that's acceptable to use inside a home. However, even food grade DE must be applied with caution:

DE is an inhalation hazard per the CDC. It can cause silicosis. It can be quite safe when used properly but isn’t as safe as some hucksters make it out to be.

and

You do not want DE in your lungs, not even freshwater DE. [..] although fresh water / food grade DE is safe if used properly, you should probably use a good respirator mask when applying any dust (such as the one recommended below), and disposable waterproof gloves when applying this or any other substance. No dust is safe if inhaled.

Also, see here:

DE is a significant inhalation hazard. While it can be applied safely (a very fine dusting barely visible to the eye only in areas where it will not get kicked up into the air), if improperly applied as we have heard about people doing, it can do significant damage to your lungs. Often, you will not see the results of that damage until years after exposure, so unlike some chemical pesticides that cause immediate reactions to let you know you've been overexposed, DE doesn't have a way to alert you that you've applied it improperly.

The general recommendation seems to be to be very careful to protect yourself from breathing in the dust using a breath mask or respirator mask.

---

• is it effective? How long does it take to kill bedbugs? Apparently, this can vary by brand of DE and there are other dusts out there that are also effective.

It may take more than a week to kill them, although whether this is because it takes that long after initial contact, or the bedbugs do not immediately come in to contact with it, may be unclear:

MotherEarth D (diatomaceous earth) was slower acting than Tempo or Drione, but caused substantial (>90 percent) mortality of susceptible and resistant bed bugs within four days and all bed bugs were dead after 10 days