Just in case anyone's still interested. I went to the University of Arizona and the University of Clemson sites. Both say that "unofficial studies suggest" that DE is effective against internal parasites. They do not say WHICH internal parasites. I would guess it matters what type of parasite it is. Most people agree that DE does not harm true worms, but it will kill on contact anything with an exoskeleton. It doesn't seem to matter quite as much whether the DE is wet or dry as it does what your target pest is. Anyone got a microscope?
