Carefully research this before you do it. Diatmaceous earth comes in several forms ranging from dangerous to extremely dangerous to breathe. No way I'd mess with it. It can cut your lungs to shreads. Like breathing tiny shards of glass.

Know what you are dealing with.

Bill

I've wondered about using kitchen flour as a dust for aphids. (or thrips)

The flour might have a dehydrating effect, like the D. earth.

I want to thank Bill. I should know better, & somewhere did.
Maybe that's why I asked. A respected rose grower suggested it & he should know better too.

Thrips have pretty much passed. Soapy water works fine for aphids & is much less messy than flour. Now it's Japanese beetles. The only solution there I know is to cut buds early in the morning & let them open in the vase. Also, I shake badly infested roses early in the morning & call "bugs, chickens!" They gobble them up like candy.

I want some ducks myself but living in a condo... I guess that will have to wait.

The info given about the dangers of DE isn't 100% correct-
Pool grade and "garden grade" DE is definately harmful to the lungs, so should never be used in a garden or around people/pets.
HOWEVER:
Food Grade DE is not the smae product. It is procecssed in such a way as to remove the harmful silica particles.... breathing it isn't nice--
but has about the same effect as snuffling a handful of baby powder!
It is bought at health-food stores or Farm / food co-ops as "Fossil Shell Flour" and is dusted onto pets and livestock; used in peoples bedding for lice, fleas and bedbugs; fed to livestock and pets to prevent worms and parasitic illnesses;
and yes-even eaten by people on a daily basis!

You can find good info in Wikipedia, and by searching the Web-- but there is a site here> http://www.wolfcreekranch.net/defaq.htm
and here> http://www.backyardchickens.com/web/viewblog.php?id=1560-Food_Grade_DE That are very informative and helpful....
The EPA also lists the areas it approves of for it's use on its site >
http://www.kellysolutions.com/AZ/showsites.asp?Basic_EPA_ID=73729%2D1&Product_Name=CONCERN+DIATOMACEOUS+EARTH+CRAWLING+INSECT+KILLER
If the EPA approves of it for use on pets and humans living quarters, then it is definately ok to use on plants..
just be sure to protect your eyes and stand upwind appying it... it isn't really harmful--
but can be nasty up your nose or in your eyes!

We us it in our outdoor garden, on our pets, in the chicken coop & run... and have had no adcerse health issues-- and we know of MANY people at out Farming sites and locals that use it as well.

Just make SURE it is food-grade DE!!!!!

"Food Grade" DE is less processed than "Pool Grade" and has sharper edges, not nice rounded shape that the "Pool Grade" has so any insect that contacts the "Food Grade" will have its exoskeleton cut and it will loose body gluids and die. Like any other foreign substance DE, not matter which, will cause people repiratory distress if inhaled, even in relatively small quantities.
"Food Grade" and "Garden Grade" DE will be the same material, just packaged differently.

Food Grade DE does not cut your lungs like glass, please show me how you determined it cut your lungs.

I used food grade a few years ago. The downside is that you have to reapply it everytime you water. It was a pain and not sure if even worked

For organic growers, DE is definitely considered an organic pest control and studies show that it doesn't cause harm to humans. My concern is that it will damage the insects that eat thrips. Thrips have many enemies including other kinds of thrips, lady bugs, spiders and many others. Interplanting with a variety perennial and annual plants will to create a diverse mini ecosystem that will support the thrip predators.