Forgot, have water meal mixed in also.

 

Only thing that ever worked for my pond and eliminated the duckweed AND watermeal was sonar. It has been 13 years since we applied and have had no issues since.

 

One $350! gallon of Sonar worked for 2-3 Years. It also killed my stately, weeping willow trees that I planted 25 years before that. I heard(or read) that Diquat kills it also and @ $75 a gallon seemed a better investment(and won’t kill pond trees)! It hasn’t worked for me on duckweed.(Was never really able to find a recommended “mixing ratio” that worked? but willing to try it again!)) There are “potholes” in low lying areas nearby that are covered w/ solid floating vegetation. One duck or goose flies from there, lands on my pond-new infestation!

 

Tsunami DQ Aquatic Herbicide 1 gallon this has a mix ratio that might be helpful.


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How much is the flow through for your pond? Is water constantly flowing through your pond? If there's a lot of flow through then sonar probably wasn't a good solution. You could try ProcellaCOR. You may need somebody licensed to apply it for you but it won't kill your willows. Once you kill it off you might need some form nutrient reduction to keep the duckweed from blooming out of control again. In my experience diquat only provides very limited relief (3 to 5 days). Most of the diquat you apply dies within 24 hours of your applying and once it's done reacting then you're waiting for the duckweed to grow back. It's really difficult to get 100% coverage unless you use a chemical that stays in the water much longer to kill kill all of it.

 

My pond has only runoff maintaining the volume. The only time the drain works/carries off excess water is just after a major rain or snow melt event. This week, I contacted the regional rep for Sepro(who manufactures Sonar) abt my particular, previous use of Sonar AS which killed my ornamental willows. He asked me for my address to get a satellite photo of my pond. He calculated the surface area(using computer software) and told me I had used over twice the amount of the chemical required and in that concentration is what killed my willows!

 

Update, after treating my pond with one gallon of the latest Sonar “Genesis” formulation for total duckweed coverage of my pond abt 10 days ago, it is about a quarter covered today and getting better every day. I’m told by the rep that this amount will not kill my remaining trees or shoreline ornamentals and will continue to curtail duckweed for at least 2-3 years, perhaps longer. Even the bullfrog tadpoles are loving it!

 

Update, after treating my pond with one gallon of the latest Sonar “Genesis” formulation for total duckweed coverage of my pond abt 10 days ago, it is about a quarter covered today and getting better every day. I’m told by the rep that this amount will not kill my remaining trees or shoreline ornamentals and will continue to curtail duckweed for at least 2-3 years, perhaps longer. Even the bullfrog tadpoles are loving it! View attachment 471601 View attachment 471601

There is a free Pond Mgmt Seminar at Great Lakes Outdoor Supply in Middlefield today from 9-3

Free Pond Management Seminar Sat. June 19 Middlefield OH | Ohio Game Fishing

 

Good, hopefully that works. Do you get much nutrient run off, and how deep is your pond? I like your pond and the view!

 

Because there‘s a lot of sand/gravel in the area, the pond was not dug(wouldn’t hold water).. Being a low area, bowl shaped, small “frog pond”: previously, the “sides had to be built up” to create a pond.(so it’s only abt 6 ft in the middle deepest part). To help compensate for the depth, I run an aerator 24-7-360. The hillside ag field next door shown top right corner drains nutrients(and who knows what else!) into
my yard/pond.(I don’t even fertilize my back yard to minimize nutrient runoff.)
Put three big weeping willows on the banks in the foreground and imagine the picture that way. They’re all gone because I took the original contractors estimate that the pond is 3/4 to 1 ac. when in fact, it is a bit over 1/2!(The pond is Hexagonal which complicates computation of actual size!) This led to “over treatment“ with the Sonar AS some years ago(which is more active than the Genesis) and killed those trees!