I've been told not to use Roundup around my pond, but to use Rodeo. Now from reading some posts on here, some people do use Roundup. I am definately not a chemistry(sp) whiz so is it a health issue or a money issue?

I understand that the surfactant in Roundup is toxic to fish and some amphibians while the surfactant in Rodeo and many other generic forms of glysophate is not.

I was told my Mississippi State marine biologist that the surfactant in Roundup was "not approved" for marine applications. He noted that this doesn't mean that it is dangerous for fish but no testing has been done to prove that is isn't dangerous.

djstauder - That is a good point, but since other products are both cheaper and approved (at least I think by the label that they are approved) then I will stay with the less expensive product.

Anyone else want to throw their opinions in on this matter? Especially the biologists out there. I will say Rodeo has knocked the hell out of the cattails.I used it once in 2010 and just used it again two weeks ago. But I do have to add the surfactant to the Rodeo.

The only difference is the surfactant. With Rodeo you choose to add an approved one while Roundup's is not approved for aquatic use.

I have used Round up and the more generic version for Alligator weed and Cat tail. I have not seen any issues with fish. Aligator weed was sprayed as a foliar spray at recommended dilution rates.

Thanks ewest. Since I already have the Rodeo, I'm not changing now. It would be great to have 8 legged bullfrogs but you would have to catch them first .

I used Rodeo and a surfactant called Dynamic for cattails, spear grass, and water lillies with great success.

There are studies of Roundup that indicate long term exposure of amphibians results in slightly longer nose length in offspring. I have not seen studies that link fish or amphibian kills directly to the surfactant in Roudup.

It all depends on where it's to be used. Roundup isn't labeled for use on or around water, where Rodeo is.

Here's what it says on the Roundup Label:

Do not apply directly to water, to areas where surface water is present or to intertidal
areas below the mean high water mark. Do not contaminate water when cleaning equipment
or disposing of equipment washwaters.

Those pesky pesticide labels; they're simply not worth the time to read - much less follow - especially if one can save a few bucks by using an off-labeled formulation, right???? ---- WRONG!!!
The tallow-amine surfactant used in many terrestrial labeled glyphosate formulations (which performs exceptionally well with glyphosate) is the primary culprit for warnings toward aquatic uses of such products. "Fish mortality" is not a likely issue. However, tallow-amine surfactants can cause several issues in an aquatic environment that are far less than conspicuous to laymen. I was informed many years ago that tallow-amine surfactants are known to cause corneal clouding to exposed fish. I haven't verified that comment's validity; but mfgrs are certainly not required to elaborately detail the reasons WHY their products should NOT be used in a specific manner or site.
Just read and follow the labels!!!! Unlike this dude.....
MN Man Kills 40k Sq-Ft Lawn "By Accident" (aka Ignorance)

That's a good one Kelly!

I've given up on telling my Dad how much weed killer to apply to his lawn. I've gone so far as to write out how much to put in the 25 gallon pull behind tank sprayer, how much should go on the front lawn, the grass on the side of the driveway, and how much to put on the grass behind the house. I've even wrote down how fast he should have the garden tractor going when he's spraying. Invaribly, he'll call and say that I didn't get him enough chemicals as he was done spraying before he finished with the grass in front of the house.......

Now I save myself the headache and just go over there to spray it for him. Mom & Dad grew up and lived in the big city, and they have a hard time comprehending that taking care of 3 acres of grass is different than 750 sq. ft. of grass. I thought they'd have learned by now, owning a different house in the country that had roughly 10,000 sq. ft. of grass for the past 40 years but sadly, they haven't.

Anyway, labels are there for a reason! If it says don't do this or that, then don't. There's a reason why the labes says what it does.

How about using "Roundup" or = to do a total kill on an acre and half area on the uphill side of a 10 ac. pond???

I don't think you'll have a problem if you watch the weather and don't apply before a rain.