Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Tempeture & Fluridone

I am looking to keep the curlyleaf pondweed under control next year using Fluridone on a 15 acre lake. Can I treat the lake once ice melts off the lake or do I need to wait for warmer water temps?


Don

In spring, I would add the fluridone when the water reaches 45F-50F or do it this fall as in late Sept or October. Curlyleaf normally sprouts and begins new growth in August and decent growth and plant activity continues down to about 45-50F. You realize that when trying to kill curlyleaf you do not need the full regular concentration of 90ppb - correct? The main goal for best kill is a very good or best distribution of chemical throughout the entire water body. Without whole pond aeration one has to rely on destratification and complete top to bottom natural mixing of the fluridone. One has to know when complete destratification starts and stops for most effective treatment.

If you are going to use fluridone to control duckweed can you use it in the fall rather than the spring? I have a big watershed and sometimes have a lot of water leave the lake in the spring. If Fluridone is effective in the fall there is less change that a big rain event will wash it away. Talking about a three acre and a one acre pond. The one acre is immediately downstream from the three acre. All water that leaves the bigger one flows into and through the small one. Right now my duckweed is under control using Diquat, but I fight it every year.

Bing, look at using Clipper for the DW.

I agree with what Bing said about water flow. The fluorine is supposed to be in contact with the weeds for 30 to 45 days, so if you apply it in the Spring make sure that there is no water flowing into or out of the body of water. If there is, do a FAST Test after 10-13 days to see if you need to bump the concentration.

If I was doing it, I'd apply the Fluridone when there is a reduced chance of water into/out of the pond - around here that means in the Fall.

Thanks Bill.
3-yrs ago I treated our 20-acre lake with 5-gallons of Fludidone and it did great applying it over 2-weeks in 2-applications. Treatment was for mainly curlyleaf and duckweed which it worked well. We started to see watermeal late August but winter was keeping it at bay for remaining of the year.
I figured applying this at around 10 ppm to keep just the curlyleaf away? I will use Diquat for contact spraying the duckweed this time.

My goal is to save our members some $$$ as we continue to install aerators throughout the lake.


70% Finger lake
20-acre lake
Average depth 12 feet is what I used to calculate the last 5-ga of fluridone that worked well on all vegetation.