Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants curly leaf infestation

Does anyone have thoughts or experience with fighting curlyleaf pond weed? liquid vs granular aquathol?
Does it make sense to try and drag some out of pond? About half an acre.

Thanks,
jim

You are better off using a low dose of Fluridone. 10 PPB dosage will kill it and not kill other plants in the pond. You cannot have water flow thru for 30 days though.

Ok will do. Thanks for help.
jim

A good time to proactively treat curlyleaf CLPW is in fall using a Fluridone based product at at 10-11ppb as noted by esshup. Curlyleaf starts growing in late summer - early Fall and then plants sit relatively dormant late Fall and winter when the water temp drops below 50F. . Then in early spring as water reaches 50F-55F it continues growing. The Fall low dosage of Fluridone will persist through winter to keep killing/suppressing CLPW. In early spring a 1/2 dose 5ppm can be applied to enhance the remaining Fluridone to knock out the plants that were not killed in the Fall application.

So should I wait now until fall. Its bad and right to the surface on 70 percent of pond.
Thanks for help guys.
jim

If you don't have water flowing out of the pond, you can treat now and it will be dead before it sets seeds for this year. Give me an accurate surface area of the pond and the max depth plus your best guess as to the average depth (measure it, don't guess at max depth). I can tell you how much Fluridone you will need to use.

Thanks Esshup!

It is roughly an oval that is .52 acres. The max depth is a measured 9 feet.

Thanks again.
jim

O.K. IF your average depth is 4.5 feet then you need 2 fl. oz. of Sonar A.S. to treat the CLPW in your pond at a dosage of 10 PPB.

Perfect thanks!!
jim

I also have curlyleaf pondweed and naiads that I would like to control with Fluridone. I have some pickerelweed that I purchased and planted and don't want to harm. This label indicates that pickerelweed is not controlled by Fluridone. Not sure if that means zero harm but sounds promising. Also, the standard dosage on that label in 90 ppb. Is 10 ppb Fluridone safe for pickerelweed in your experience? I think so.

https://www.solutionsstores.com/amfile/file/download/file/1779/product/618/

90ppb will impact pickerelweed.
If it was my pond, I'd treat at 10 ppb with Fluridone and use Aquathol Super K to spot treat *some* of the naiad.

Could I pile on here and get some advice for the same problem. I have a 1/3 acre pond that is 12' deep in the deepest section. I have Curly Leaf Pondweed (CPW) that has been limited to a small area near my dock, until last year when it took off and spread all over the pond. The other predominant plan is Chara, which covers most of the pond bottom. Prior to the Chara and CPW I fought a constant battle with FA. Since the Chara and CPW gave me clear water and no FA I've just been living with it. The CPW is suddenly spreading very aggressively so I'd like to try this low dose Fluridone, but what will be the effect on the Chara? Is there something I can plant to replace both of these weeds?

The pond is well fed with no outlet. Stocked with Rainbow trout. Aerated at the 8' depth.

Unfortunately if you wipe out both the Chara and the CLPW you will be fighting the FA most of the year. I'd try just wiping out the CLPW and the Chara in the areas that you want to fish.

Treat the CLPW in late September or early October with the Fluridone.

It sounds like I'm between the proverbial rock and a hard place. I would much prefer to deal with short term pain to achieve long term gain. I don't really fish much in the pond, the trout are there to fill the role of the top predator. Also, I was under the impression that your low dose technique eventually kills ALL the CLPW, and it sounds like it will kill the Chara as well.

Rather than stop gap measures what would you recommend to fix the invasive weed issue? I assume I would use your low dose regime and then come in and plant beneficial pond plants? If you have specific recommendations on how to remediate this pond, or if you can point me to a "how to" on the forum I would greatly appreciate it. I've done a lot of searching but have had no luck finding advice for a trout pond in the Northern Rockies.

TIA

Errfoil, sorry for the mis-understanding. The Fluridone will NOT kill the Chara. I have never seen it work on Algae - Chara is a type of Algae.

I'd do a low dose treatment of CLPW in the Fall after this years seeds sprout, and plant beneficial native underwater vascular plants to re-populate the pond.

Esshup, would grass carp work to reduce CLPW and not impact Chara? I don't know if there is a "permanent" fix for CLPW since it appears to be transported by geese or other waterfowl that don't "Clean, Drain, and Dry Your Boat and Gear" after leaving infested areas.

The Triploids will eat it, but if there are other "weeds" in the pond that they prefer (like most native plants) they will eat the CLPW last.

esshup, that is great news. This means I can attack the various problem plants piecemeal vs nuking the whole pond. A couple of questions; what dosage do you recommend for a 1/3 acre, 14' deep pond? Second, why wait until they produce seeds, wouldn't it be better to knock them down now before they go to seed, not to mention a summers worth of propagation?

I'm not sure the Fluridone will work fast enough to kill the CLPW before it produces turions and seeds in your pond. IMO you are rather late in the season for your attempt to kill your CLPW. Ideally the CLPW should be treated as soon as the pond water is 55F when CLPW starts growing fast. . Because you are in north Montana and CLPW matures later in the year compared to more southern states the Furidone might stop the current CLPW growth infestation before it makes the dormant or winter buds called turions and also the annual seeds. Check numerous near surface plants in 2 to 6 ft deep to see if turions have formed in the places were many of the leaves join the stem. See a large turion in this link - Turions are not always this large, some are smaller and still capable of making new plants
https://extension.umn.edu/identify-invasive-species/curly-leaf-pondweed
https://www.montana.edu/extension/i...sion_publications/Curlyleaf_pondweed.pdf

If your plants have turions then IMO it is almost fruitless to spend money killing the CLPW now because the chemical will NOT kill the turions. Turions sprout in early Fall or Spring and can lay dormant and sprout in 1-2 maybe 3 years later. CLPW is a pest and truly an invasive persistent species. Wait and use Fluridone in Fall or early spring 2025.

What I have done in your current time limited situation is do a fast kill with diquat either Reward or Harvester or similar brand name. Be sure to use the one with strong active ingredient of 37.3%. Montana Extension suggests to use diquat early in the season before other good submerged pond plants are actively growing. this means an early Spring treatment water around 55F-60F.
Diquat works best when water clear and often does not do a real good kill if the water is murky and silty. Diquat will kill most all submerged leafy plants, HOWEVER it will NOT kill Chara since as esshup says it is a higher form of problematic algae difficult to kill. . Read the label for proper usage. For ponds with depth esp 10-14ft I ALWAYS inject the chemical dosage into the deep pond layer to make sure all the CLPW absorbs the chemical for a good kill. I also inject deep the Fluridone when I use it in the Spring treatment. If you apply the diquat properly at the right concentration the CLPW should be turning brown and dying in 5-10 days.

Once you get the CLPW killed back, I always use Fluridone in the fall and/or early spring for another long term kill time as the old dormant, resident turions and seeds sprout during the next 2-3 years. You will fight CLPW for several years or longer due to late sprouting turions and sheltered plants that do not get killed with each herbicide treatment either with diquat or Floridone. Floridone is actually best to use because it is active and kills a long time for each treatment working on dormant turions as they sprout. Low dosage (10-12ppb) or concentration of Furidone often does not kill other beneficial pond plants. When you use the low Fluridone dosage it is best to apply a 2nd bump or refresher (5ppm) dosage 10-20 days after the first application.

Bill, The Montana Extension document suggests that raking areas over 3-4 years can be effective at keeping CLPW under control. Have you seen this to be the case, or is there reason to do this in combination with chemical treatment?

My go-to method of control is Fluridone in the late Fall. 7-10 PPB is all you need Way less labor intensive than raking and it doesn't miss a plant. WAAAYYY less labor intensive.