# Pondweed



## Lundy (Apr 5, 2004)

Is starting to piss me off.

I have sprayed twice with Weedtrine D, cutine, surfactant mix and it does knock out most of it but some just comes back. Within hours of spraying it is all brown and a few days later the leaves turn back to green but with many less leaves.

If I spray with Aquathol K will it kill these things once and for all?

I do not have much pondweed left but what I do want to completely eliminate it.


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## Lewis (Apr 5, 2004)

Not to hijack your thread Kim,but maybe you or someone can help.
My brother just had a 3 acre pond excavated this summer.
On one corner of the pond site stood a small 100 square ft. water hole which held a thick coating of Duckweed.This waterhole was released into the new pond during excavation.
The barely filling pond now has a mat of Duckweed on one corner.
Should this be chemically treated now or should we wait until the pond fills?


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## [email protected] (Feb 29, 2008)

Endothall or dipotassium salt of endothall (the active ingredient in Aquathol K) is the preferred treatment for all of the potamogeton spp. (pondweeds). We recommend mixing it with the cutrine in equal parts for pondweeds. My experience shows that nothing "kills it once and for all" though. According to the Army Corps of Engineers, diquat provides good control of pondweeds while endothall provides excellent control. 

Lewis treat the duckweed now. Spray the plant with a fine mist of diquat about every three days until it is gone. Mix 2-4 ounces of diquat per gallon of water and try not to wash the chemical off the plant by creating any water turbulence. If the duckweed gets out of hand you are left with no choice but to use fluridone which is very very expensive.


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## Lundy (Apr 5, 2004)

Thanks Lucas, I'll be ordering the 2-1/2 gallon container of Aquathol K. What is up with the 2-1/2 gallon size and no 1 gallon sizes? I hope it doesn't have shelf life because 2-1/2 gallons will last me a long time.

Lewis,

As you know I had a huge problem with duckweed and watermeal 3 years ago. I used a fluridone product and wiped it out completely, but as lucas said it was not inexpensive.

This year I found maybe 100 duckweeds hiding in the pondweed when I was spraying the pondweed. The mix of Weedtrine D, Cutrine + and the surfactant killed them all by the next day. I checked that area everyday for a week and the rest of the pond and haven't see any since. Duckweed is amazing at how fast it can multiply, don't let it go or you will be faced with only one option to get rid of it.


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