I thought when using DE you are to use food grade. After reading on BYC, we have decided to not use it because it can be harmful to honey bees and other good insects. Since we have our first hive this year on our farm and want to add more in the near future, we are going to use the wood ash as some have suggested.
Can you supply a reference link for this 'fact'? I would love to read it.
DE, plain and simple, is like superfine sand....
sand is largely silica... as is DE (80-90%). The remaining ingredients are all typical earth elements found in soils everywhere. Its ability to 'kill' insects relies on the microscopic sharp edges of the crystalline structure of these fossilized algae diatoms. It has nothing to do with the chemical makeup of algae per se or that of any 'chemical' nature... but relies on its purely physical/mechanical means of death to the insect... which is a very environmental manner of pest control. The type of insect that is targeted by the use of DE is to the greatest extent,
soft bodied crawling insects, i.e., slugs, snails, ants, lice (including aphids), mites, etc., which is why it's been used in organic gardening practices as a pest control for decades. The insect crawls over the microscopic 'knifeblades' of the crystalline DE lacerating its body which causes moisture loss/dehydration and ultimately death. Nothing at all to do with chemistry or a poisonous nature. The reason that DE isn't effective when it gets wet is that it has a tendency (as most earth elements) to bond tighter together (clumping) ... which greatly reduces the sharp cutting surfaces.
As you mentioned
pickitfarm, one 'SHOULD' always use food grade when using around animals. I didn't include any mention or reference to that as it was my intent to clarify what Diatomatious Earth (DE) is and not the specifics of how/what to use. Food grade is only a higher quality from the refining aspect as DE is mined from the soil not made in a lab.
So in being
harmful to honeybees and other good insects ... the answer would be ... highly debatable! Since bees are typically a flying insect and not a crawling insect it would be quite negligible in its harm to them. It would be somewhat harmful towards some beneficial insects, the predators of pest insects like minute pirate bugs, lady bug larvae, aphid midges, lacewing larvae, etc., if applied in those areas that they would likely habitate. However, your chickens shouldn't be infested with those (beneficial) type of critters nor should their 'house/run' be infested. Those beneficial critters live on
plants and DE is used (regarding chickens) on the chicken's body, in and around the house and in the run areas. So yes, you could say that DE could be harmful to beneficial (garden) insects but those insects very rarely inhabit the areas that the DE would be used and since it is not a chemical spray like so many commercial garden insecticides, it doesn't have a poisoning effect drifting through the air as you apply it.
A side note to any harmful nature that DE could pose to beneficial insects, when used on chickens and in and around the chicken house/run areas.....
........ DE is not as harmful to those insects as the chickens are themselves... don't know about other people's chickens, but all of my chickens (and chicks from about 10 days old) eat every crawling thing (protein) they can see and find. That's even more effective at killing beneficial garden insects then DE, as its effectiveness is lost once wet... while the chickens keep on working....
P.S. --- I also have a Kenyan Top Bar Bee Hive and my bees don't seem to have a problem... but they stay away from the henhouse because there is no nectar there.