The important practical difference is that metaldehyde is poisonous to humans and pets (and birds, etc) whereas iron phosphate is not.

i appreciate that you think i know it all .. lol

but i have no clue how either works ...

ken

LOL Ken. I thought I remembered you saying something like with [one], they go away to die. with [the other] they die right in your garden
.... does that ring a bell?

The big difference I've noticed is that when they eat the Sluggo, they GO AWAY to die. With anything that has metaldehyde in it, they die on site and I end up with piles of slmimy snail shells and slugs. Yuck. Perhaps they get constipated from the iron? (Haha)

-Babka

Here is an article from the Library with links to research, that might fill in some background.

Here is a link that might be useful: Slug and snail baits, Hosta Library

Found the post.... and Ken, it wasn't yours. Sorry.

Around here Bug-Geta kills the slugs and snails but their bodies and slime are there the next morning.
With iron phosphate (Sluggo) they eat and go away to die. When the bodies are left, other slugs and snails come running to eat dead ones. I use Sluggo all year around and just consider it part of the expense of having hole free hostas, tomatoes, pansies, impatiens, citrus liriope mondo, etc.etc.

-Babka

he he. Thanks Babka. We must've both had our posts working at the same time! LOL

I was advised to use Sluggo by a hosta grower here in Ontario but with our strict pesticide laws now, it really difficult to get anything. Apparently, we can buy it here if we are farmers - how does one prove they are a farmer?!

I recall reading once that Iron Phosphate makes them unable to eat and they starve to death.

There now is Sluggo Plus (and facsimiles) that contains Spinosad (a BT-like organic ingredient) which also goes after earwigs. I think the earwigs are nearly as destructive as the slugs.

Bill Meyer posted this on Hallson's forum. Perhaps Sluggo is not as safe as thought.

by Bill Meyer Jan 05, 2010 9:57 am

Hi Everybody,
I've had doubts about those iron phosphate slug baits for a while now and recent studies are starting to come in that raise very real questions about how these products got the reputation that they have.
These products are sold as "safe and non-toxic" in their advertising, based on the claim that they use only iron phosphate to kill slugs. The ingredient labels show only 1% iron phosphate under active ingredients and 99% inert ingredients. The latter is wheat gluten. Actual analysys however shows that they contain over 1% EDTA in addition.
If these slug baits really were what their label says, they would be as safe as they are advertised to be. They also would not kill any slugs or snails. It is only the addition of EDTA that makes them work, and that EDTA makes them far more poisonous than they are advertised to be.
In Switzerland (study below) the organization that decides if a product is to be certified for organic farming reviewed these baits and denied them because of the EDTA. In their report, they said that EDTA is more poisonous than metaldehyde and that they didn't think the products would be much safer than metaldehyde baits. This is turning out to be true, as animal poisonings are starting to be reported.
Below are links to two reports of dogs being poisoned, and the Ohio State study (also below) says the EPA reports "5 domestic animal deaths, 8 major domestic animal incidents and 106 moderate and minor domestic animal incidents from the use of iron phosphate slug and snail baits". These products do not contain Bitrex as do the metaldehyde products, so they are more likely to be consumed by pets and widlife, and worse yet by children. These are mainly caused by iron poisoning, which is very serious itself. Additionally, excess iron builds up in the system and is very hard to get rid of so continually eating small amounts of these pellets slowly increases the amount of iron in the system until it reaches toxic levels.
I have contacted the EPA about this, and others have as well. I think we'll see a re-evaluation from them in the near future, but I don't know how long that will take. It will almost certainly involve reclassifying these baits as poisonous and requiring that the EDTA content be shown on the label.
If you have these products or are planning to use them, I strongly recommend that you treat them the same way as you would the metaldehyde baits, and consider them equally dangerous until we know more about them. Be extremely careful to keep children and pets out of the containers. Use only sparingly as directed, don't put big bands or piles anywhere, and clean up spills. Do not allow children or pets to play unsupervised in treated areas, and watch for neighbor's dogs or kids when the product is down.
It is ultimately our responsibility to keep kids, pets, and wildlife safe from poisoning when we use or store poisons. Both metaldehyde and iron phosphate baits are pretty safe if used properly, but they are both dangerous poisons. Remember too that the iron phosphate baits as far as I know do not contain Bitrex so they are much easier to eat in large quantities.

.......Bill Meyer

Dog Poisonings:
http://www.ingentaconnect.com/content/bpl/avj/2009/00000087/00000007/art00011

http://blog.oregonlive.com/pethealth/2008/07/gardners_beware_of_socalled_pe.html

Earthworm Poisonings:
http://www.biosci.ohio-state.edu/~soilecol/Full%20articles/2008/Crop%20Protection%2028.pdf

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T4B-4JKJT15-1&_user=10&_coverDate=12%2F31%2F2006&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=f73325d8a5e3b2c97804dd3ac845cb8c

Swiss Investigation for Organic Certification:
http://www2.eduskunta.fi/kerhot/luonto/eurosiili/pdf/FIBL_FeP_Jan06_E.pdf

Sluggo Label and Advertising:
http://www.montereylawngarden.com/pdf/sluggo_03_bilingual.pdf

http://www.neudorff.com/index.php?id=181

http://www.growercentral.com/UPLOADS/PDFS/ferramol%20brochure.pdf

NY Department of Environmental Conservation Statement:
http://pmep.cce.cornell.edu/profiles/insect-mite/fenitrothion-methylpara/iron%20phosphatic%20acid/ironphosphuricacid_500.pdfIf you thought the auction was fun, come to the meeting!

I've used both baits and found metaldehyde works better and I rather like seeing the slug carcasses as proof that the stuff is working.

Mark

Someone posted that here too.