DE has been found to be a useful insect/parasite killer and can be used in several different ways to aid in your efforts at a more natural pest control. I use DE several different ways.
1. Internal Wormer.
*I now choose to only treat for worms when an infestation is evident. Healthy pets should not be routinely wormed just because. A properly fed & Naturally Reared dog/cat in a state of Homeostasis should be able to keep parasites in check, there is even evidence that a healthy animal's immune system can BENEFIT from harboring a minimal amount of internal parasites and that this helps them stay free from chronic illness. Here is a link to further information about this fact:artoverwoming
In the past, I have given DE every day to eradicate/control internal parasites, such as roundworms, hookworms, etc. To my knowledge DE does not kill heartworms.
Some people use DE twice a year, for 60 days at a time. Throughout my research I have found out that DE cleans out bacteria and heavy metals out of the body, also that it continues working in the stool to kill flies. These reasons are why some choose to give it 365 days a year.
Here are general guidelines on dosage.
Kittens - 1/2 to 1 teaspoon
Cats - 2 teaspoons twice/day
Puppies 10 to 19 lbs. - 2 teaspoons
Dogs 20 to 50 lbs. - 1 to 1.5 tablespoons
Dogs 50+ lbs. - 2 tablespoons
Dogs 100+ lbs. - 3 to 4 tablespoons
If you feed kibble, have a dog that is prone to constipation or use a brand that has has added Calcium, watch you dog for a few days to make sure the DE does not constipate or dry out their stool too much. I have never had a problem with this but some people worry about it. If this did happen my recommendation would be to reduce your dose of DE, make sure your dog has access to unlimited clean water or if you feed a raw diet, feed a bit less bone daily.
I use DE directly on my dogs to help control fleas and ticks. DE is a mechanical killer, which means it kills via a mechanical/physical means rather than a chemical that kills. DE is made up of microscopic particles that are extremely sharp and these razor sharp particles cut the parasite's exoskeleton and then the particles dehydrate the insect, due to the DE's honeycomb hollow shape. DE particles are to small to harm your pet. They are microscopic algae particles! DE is also known to kill bedbugs, and many harmful garden bugs. I use a "puffer"(sort of like a bulb syringe) or pantyhose/knee high to apply DE directly to my dogs. Just pour in about 1/4 cup and loosely tie off the end, then rub the hose over the dogs fur. You want to get it all the way in to the skin. You can use the "applicator" to get the DE all over your pet's body, including underneath and down the legs. You can also softly tap the stocking against your hand your pet's body to apply it heavier. Whatever works best for you. Try to do this outside as you should avoid breathing in the dust, it may irritate some people's(or dog's) sinus, throat or lungs because it is so fine. If you cant use it outdoors, try to find a well ventilated area.
repeat application about twice a week and after baths/swimming.
I use DE in my dogs crates for additional flea control.I clean the tray, then puff some DE then put down the blanket/towel then puff some more DE in on top of the blanket. Do not immediately put your dog in the crate. Do not completely cover the crate with the dog in it, especially until the DE gets worked into the blanket. It may irritate his lungs if he breathes too much of the dust.
I use DE on my yard to kill fleas, flies, ants, etc. I usually apply it by hand or with my "puffer". There are usually directions on the bag for recommended amounts. You can also mix DE with dry sand and use a spreader.
DE can also be applied around the foundation of your home to help with pests/bugs. I used the puffer after the block foundation was mostly finished to get the DE around under the house and at the base of the foundation.
I keep chickens for eggs and meat for the dogs. I add DE to the Chicken feed. this helps control parasites like worms, giardia and flies. The chickens poo it out and so it continues working to help control the fly population! This also is a organic way to keep the chickens healthy and disease free. We also use DE in our pig's food as wormer/fly control.
I do know that DE works. Here are the details of my DE Experiment. Anyone can do this at home all you need is some DE, a baby food jar or some other see through container with a lid, a flea or two, and a tick or two. Having had a pretty warm winter, flea & tick season is already upon us here in East Tennessee and I do check all four of my dogs for ticks several times per day. After letting my pack out the other morning I found a tick crawling on Cooter's fur. I grabbed it and put it into the container with some DE. That evening I found a small flea that had hitched a ride on Daisy, into the container it went as well. The tick was vigorous and crawling all over the place when i put it into the jar, within an hour it's movement was noticeably slower. Within 2 hours it was having serious trouble righting itself if it got turned on its back, and within 6-7 hours it was dead. The flea was small but vigorous as well. Same thing, within just an hour it was sluggish and not moving or jumping as much. Within 3-4 hours it was dead. My conclusion is that while DE id not an immediate kill, it does kill fleas and ticks within a reasonable amount of time. I have read that sn infected tick must be attached/feeding for about 36 hours before it can transmit Lyme Disease.