Fighting the same situation on a 12 acre lake in NC. Did a huge amount of hand work last year with some success. Also tried the Aquacide Pellets which in my experience did little or nothing.
Questions on the Ecomazapyr for the experts out there:
1). Our dogs and some swim in the lake pretty much daily. Any safety concerns?
2). Maybe I am just missing it or too inexperienced with all of this, but looking over this thread I guess I do not really understand what ratio to mix. For example, if I am spraying round up on my lawn I buy the concentrate and use X tablespoons per gallon to achieve the desired concentration in my sprayer. What ratio should I use with a large back pack sprayer and the Ecomazapyr?
My simple answer is to read the label on the bottle. It will tell you how many ounces of herbicide to use per gallons of water to cover "x" amount of pond surface area.
This is what I posted in this same thread above: Figure out the area that the watershield is covering and apply the Ecomazapyr at the rate of 2-4 pints per acre, and mix in the surfactant at the rate of .16 to .64 fl. oz. per gallon of tank mix.
If you mix the solution too strong (more is NOT better when it comes to herbicides to control plants) you can shock the plant and it basically shuts down, NOT translocating the herbicide to the roots where it's supposed to go to kill the plant vs. just giving it a haircut. You did the correct thing, applying it in the Fall when the plants were taking nutrients down to the roots for the winter.
I would also mix in some pond dye to the tank mix so you can see where you sprayed and so you don't over or under spray an area.
Go here:
https://alligare.com/products/ecomazapyr-2-sl/, scroll down and click on the green label tab. You will want to read page 8 and 9.
As for the pets, if applied per the label, there are no restrictions for livestock.
If using a backpack sprayer, you will have to carefully figure out how many sq. ft. of the pond surface you can cover with the amount of herbicide you put in the back pack sprayer.
