Pond Boss
Posted By: Todd Strohecker Duckweed control? - 04/09/03 02:13 PM
What do most of you use to control Duckweed? Anyone use Opti-amine?

What rates do you apply it for Duckweed?
Posted By: shan Re: Duckweed control? - 04/09/03 02:55 PM
Reward (active ingredient = diquat) will knock duckweed back very well. you need to be persistant with this herbicide to eradicate duckweed.

sonar or avast (active ingredient = floridone) will eradicate duckweed well. will require repeat treatments if the pond has flowing water.
Posted By: shan Re: Duckweed control? - 04/09/03 02:56 PM
Reward (active ingredient = diquat) will knock duckweed back very well. you need to be persistant with this herbicide to eradicate duckweed.

sonar or avast (active ingredient = floridone) will eradicate duckweed well. will require repeat treatments if the pond has flowing water.
Posted By: Greg Grimes Re: Duckweed control? - 04/10/03 02:48 AM
I agree with Shan. I advise pondowners to hire me for the first treatment with Reward (and take notes), but do it themselves after the first application. You really have to stay on top of it to compeletely eradicate with Reward, but it can be done. The 3% that is not killed will quickly take back over if not retreated.

When using Sonar we will siphon or pump the lake down so the required ppb concentration is maintained for at least a month. It has worked 3 out of 4 times to control duckweed or even worse watermeal.
Posted By: Kelly Duffie Re: Duckweed control? - 04/10/03 04:03 AM
Todd: Never heard of OPTI-AMINE, but suspect it is a formulation of 2,4-D Amine - which is completely ineffective on duckweed, as is glyphosate (in case you should ask).

As for diquat (REWARD) or fluridone (SONAR): IF the pond is static or has very little potential for a flow-through event, and IF more than 50% coverage (assuming at least 1 to 2+ acre pond size), I'd lean toward using fluridone - especially if your application equipment is limited to a low-volume (hand-held) pump-up sprayer. On the other hand, IF your pond regularly experiences flow-throughs/over-flows, or has a high likelyhood of same with minimal rainfall, REWARD may be your only practical option. However, it is best to conduct REWARD treatments before the infestation reaches severe levels, since REWARD must contact all plants that are expected to secumb to the treatment (add CIDE-KICK to REWARD to increase it activity on the targeted plants). With REWARD, use the wind to your advantage. Treat (with the wind behind you) from a boat (pref a 12v ATV type sprayer) when the wind has the duckweed concentrated along a windward shoreline. Strive to contact as many of the duckweed plants as possible with the initial treatment (2 gal. REWARD per TREATED surface acre, diluted in enough water to allow thorough coverage). Conduct REWARD RE-treatments to surviving plants within 3 - 6 days. Otherwise initial-treatment survivors will quickly replace what plants were successfully controlled. Multiple duckweed re-treatments are the norm with REWARD, though each successive treatment should require much less product and time than the prior treatment. Use clean water ONLY when tank-mixing REWARD (muddy water ties up with diquiat very rapidly).
SONAR usually requires only one whole-lake treatment - dosing at 6-8 oz. per acre-foot (under conducive circumstances). Satisfactory control may last beyond one season, unless a reintroduction of the plant should happen, or a flow-through event occurs within the first 30 days after the treatment. SONAR requires this 30-day length of contact-time to impart its effect on susceptable plants. SONAR applications require only a bucket or pump-up sprayer. SONAR's dilution-ratio in the mix-tank is irrelevant - the proper dosage is based on amount of undiluted product in relation to the volume of water in the pond. Focus on achieving and maintaining the targeted concentration for at least 30-days (measure in parts per billion - ppb).
Unlike REWARD, fluridone is applied INTO the pond's water-colume as a properly-dosed pre-diluted solution (Do not apply fluridone solution on top of duckweed infestions. Direct sunlight quickly breaks down fluridone). Alternately, REWARD must be applied as a topical spray to all targeted plants.
Lots of "ifs" and requirements to consider in this thread. Any questions? Let me know.
KD
Posted By: Todd Strohecker Re: Duckweed control? - 04/10/03 01:50 PM
Thanks to all that responded.

Yes, the Opti-Amine is a 2,4-D. It was in an older "Green Book" os registered pesticides.

The duckweed is not out of control yet so the Reward should work fine.

I really like what I have read and heard about SONAR. It has a lot of good attributes but it seems pretty pricey.

One more quick question.

Can SONAR be used in mid summer on large amounts of Eurasian Milfoil without the fear of killing it too quickly and depleting the oxygen for bass?
Posted By: Kelly Duffie Re: Duckweed control? - 04/10/03 07:10 PM
SONAR's effect on suscepable species is anything but quick. However, when things do happen, they generally happen all at once. So yes, there could be concerns about a mid-summer fallout of EWM and the potential impact on DO by its decomposition.
However, possibly of greater concern is IF the SONAR would work very well with a mid-summer treatment (maybe not). SONAR's mode-of-action requires active and sustained growth from the targeted plant(s). If, by mid-summer, the EWM has topped-out and its growth rate has drastically declined, SONAR may provide less than optimal results. Best to treat in the spring when new growth is most active.
Posted By: Todd Strohecker Re: Duckweed control? - 04/11/03 12:52 AM
Thanks KM. This site is full of knowledge and knowledgable people. Once again, thanks to all that responded.
Posted By: lakedoctor Re: Duckweed control? - 04/11/03 05:18 AM
I really have to jump in here somewhere, I don't think this is all that much to deal with because it is one of the most common pests it has a cure.Sonar,if it is applied early. Get it knocked down.Touch up if you have to with Reward then forget it was there.Drain it down if you have excess flow. Throw in the Sonar and let it work.DOC
Posted By: Kelly Duffie Re: Duckweed control? - 04/12/03 06:21 AM
Doc: While most lake management professionals are familiar with various management options, methods and treatment techniques for nuisance aquatic species, I think it presumptuous to expect the same level of experience from those who visit this board for information and guidance regarding their questions. If I ask important questions to a medical doctor, I expect thorough answers and responses to “what-ifs” in a language that I can understand. “Throw in a few aspirin, knock ‘em down with some Jack, touch it up the next morning with a Bloody Mary and forget you were sick” isn’t going to satisfy my expectations. Maybe I’m wrong, but I suspect laymen pondowners may feel the same regarding their questions (which lie outside their fields of expertise). Just thought I’d jump in with that opinion. No offense intended.
Posted By: Bill Cody Re: Duckweed control? - 04/12/03 03:18 PM
NO offense here either but I tend to agree with Kelly. If you are going to run under the title of lakedoctor (which implies you are a true profesional) you shouldn't expense weed treatment advice casually and sound like a bar tender giving advice to a patron. Most of these herbicides are when in the jug "strong chemicals" and should not be treated lightly or casually. Casual handling and lack of respect and NOT closely following label instructions and application directions are ways how many persons produce poor results with use of these chemicals. Improper use is common with many casual users of herbicides which is why EPA is restricting their use and requiring an applicator license for use for more & more of the herbicides/persticides. Too much misuse.

Duckweed and water-meal are common weed problems as you say, but they are also environmental indicators of highly eutrophic conditions within the pond. When you have abundant duck weed, your pond is telling you, no it is screaming, that it is very fertile or over fertile and a fish kill is VERY likely due to the over enriched conditions. If you have frequent duck weed problems the pond owner should be very concerned with the conditions that causing it to grow very abundantly. The owners should be investigating, exploring and or doing management practices to reduce the conditions that are causing the duckweed problem. If those causative agents are not addressed the pond will continue in it's rapid downward spiral (pond succession). RIF one can reduce the causative agents, it will slow the aging process of the pond and maybe reduce or eliminate the duckweed problem plus reduce the chance for a fish kill. Often due to pond design or location, it is not feasable to reduce the causes of duckweed. Then one has to deal best they can with an aged pond.
Posted By: lakedoctor Re: Duckweed control? - 04/12/03 10:01 PM
You are right advice should not be handed out lightly but after reading the post that had already given the technical side of duckweed control I wanted to give a simple direct and to the point post that was easy to read and understand but maybe I should have put a warning about following label directions.But I thought you guys already had that covered. If a reader is after information on a certain subject they should read all the post and make their mind up how to go about solving their problem.If I caused any problems with this post I am sorry and will try not to let it happen again but in this time of the year I get in the hurry mode and don't slow down till winter my better half has to almost tie me to the chair to get me to take time out to eat supper thanks for letting me have it I need it once in awhile. DOC
Posted By: Bill Cody Re: Duckweed control? - 04/13/03 12:34 AM
LkDoc- Its your 'neck stretched out there' no one elses. The problem is that SOME people do not read all of the posts or only remember a select few; so one should always try to provide the best you can each time, just in case the reader remembers or selects only your advice.
Posted By: lakedoctor Re: Duckweed control? - 04/14/03 05:26 AM
Bill I do feel some of the people that come to this forum don't want a long drawn out post with alot of techical terms that only a pro can make any since out of. I received an email that explained that the post should be in plain talk and to the point. I don't want anybody that reads these posts to just go out and blindly do something just because I said to.I want to give people as much help as I can but in the end they are the ones that make the decision on their actions.I cannot be responsible for the results if I am not doing the hands on.I charge people good money just to show up and give them the 411 on any problem they throw at me about their lake or pond. But on here I get to sit here and relax and not worry about the business part and still get to help in some small way some of the readers.I like it when I get an email from somebody across the country just to say thanks and that's a pretty good pay off.Almost as good as getting a check .DOC
Posted By: Bill Cody Re: Duckweed control? - 04/15/03 02:45 AM
LkDoc - I'm sure you are right about what most readers here want in an answer. Posts do not have to be "long drawn out and full of technical terms" which are often features of my answers and often not the best approach for most.

Bob Lusk is a fine example of short and simple common language posts. One can use his style as an excellent example or mentor. He is not a frequent contributor when fish season keeps him on the road. But you can search his past posts for examples of what I am refering to. He does an excellent job in my opinion and I enjoy reading his style.

I think what KD an I were referring to was a style that 'we felt' maybe was too casual when dealing with herbicides which should always be considered serious stuff esp from a professional with training. Your style must have rubbbed our 'chemical feathers' the wrong way. However non-herbicide answers can be very casual and 'local'. I'm positive KD takes his herbicide stuff very very serious and I tend to agree with him. I think people in general take plant control & herbicide application way too casually and they need to be constantly reminded of the serious nature and consequences of hebicides and improper application. I think this is the point we were trying to make to you. I had several heated posts/discussions with KD before, I know where he is coming from. I had to learn not to take things here personal; they are not ment that way and intent and inflection are often very hard to convey with written words. As we said earlier no offense and don't take it personal. Everyone here is entitled to their opinion and as you know you are allowed to respond in most any manner at this forum. I guess that is what the rating system is all about, but not sure how effective it is.
Posted By: shan Re: Duckweed control? - 04/15/03 03:45 AM
Not to beat you up lakedoc. I catch myself making general statments here as well. but chemcial application advice needs a little more attention.

I have posted this before but I'll do it again. A few years ago I was spraying Reward on a very windy day. my sprayer is driven by a 5.5 Honda and puts out 9 GPM (max) the mist off the gun can be significant. I accidently caught a breath of that mist and it burned the hell out of the inside of my nose. I had nose bleeds for weeks. it took quite a bid of flushing (and all my drinking water) just to be able to drive home. I thank goodness I had enough sense to put my goggles on that day.

needless to say I look like the poster boy for chemical application saftey these days. be careful with these aquatic herbicides boys. wear your gloves, goggles or face shield, long sleeves, etc. you dont want it on you, I promise.
Posted By: lakedoctor Re: Duckweed control? - 04/15/03 07:15 AM
I get the point that you guys are trying to get across and your right.I don't take chances with herbicides.I always take the extra time to make safety my #1 priority.The thing that was missunderstood in my post was that I had read your post and believed that all the bases had been covered to the point a person not in this field would log off scratching his head and getting discouraged and confused.I think and believe that the chemicals that we in the field use everyday should be restricted.That is not the case in In.The only restricted chemical that we have or use is rotenone.Does that seem alittle crazy to anybody.I Don't want to step on anyones toes but I and I'm sure that anybody that is in this field has to be licensed and trained to apply these chemicals at least for hire.Is it in your or my best interest to post and explain the way to treat with these harmful chemicals.Ask yourself if you would hire anybody off the street give them a job without at least spending a good amount of time training them.Do you think that it is wise to post a treatment plan to someone that you have never even seen.That is alot of risk and I'll bet in some cases has had some really bad results.I just want to give a little different angle to these chemical treatment post maybe the best advise that we could give is the name of a pro in that persons area. DOC
Posted By: shan Re: Duckweed control? - 04/15/03 01:44 PM
lakedoc,

georgia is the same. anyone can buy herbicides for treating thier pond. I'm not sure if making everything restricted use is the answer not everyone can afford a consultant to treat their ponds.

I pick up several jobs a year from other "lake management" companies around here. they ususally hire high school kids to treat their ponds. the kids usually over apply copper or treat too much of the pond during the summer. their poor results are great for me, I like new work.
Posted By: Kelly Duffie Re: Duckweed control? - 04/17/03 04:57 AM
Doc: I can't stay on the sidelines any longer. I have to address some of your comments:
1) The OMISSION of information, rather than TOO MUCH information, produces more confusion and discouragement (esp. when undesired or catastrophic results occur due to an improper treatment).
2) Restricting chemical access (through licensing requirements) is comparably effective as our present narcotics laws (nuff said). Better educational efforts are crucial in both areas.
3) Ironically, rotenone is a naturally occuring substance (produced from roots of the cube tree). Only rotenone's aquatic-labeled formulations are "restricted-use"; more than likely due to past malicious uses (harvesting fish from a trespassed pond by the light of the moon???). The small-package formulations of rotenone are "general-use" insecticides for many types of ornamental garden pests.
4) At least in TX, commercial applicators of general-use herbicides to private ponds/lakes outside of incorporated city-limits do not require a applicators license. However, if I were hiring someone for such, I'd AT LEAST make certain that they were licensed (although that piece of paper no more guarantees a proper pesticide treatment than a drivers license guarantees proper driving habits).
5) In many situations, treatment "suggestions" may be accurately dispensed on boards such as this, but only IF a qualified person takes the time to ask the right questions BEFORE firing off a recommendation. Never shoot from the hip!
6) When properly and appropriately employed, these so-called "harmful chemicals" are very useful and environmentally compatible tools (BC: let us avoid another debate here. The thread is already too lengthy.)
My earlier posts may be too wordy; maybe not. But, if anyone reads my posts and is "confused" by what I've said, I guess I've either grossly failed OR they probably shouldn't attempt feeding themselves without supervision. KD
Posted By: Dave Davidson Re: Duckweed control? - 04/17/03 11:41 AM
OK Kelly, Sign me up for Eating Only With A Spoon. My wife already says I need a bumper sticker saying "Doesn't Play Well With Others".

I'm curious.

Regarding # 4 your above post; I assume Rotenone is not a general use herbicide but in # 3 you mention its availability in small packages as a general use insecticide.

How small are the packages and in small lots are they affordable to someone who wanted to clobber a pond in the middle of the night or just bypass the cost of a commercial applicator?

Enjoyed meeting you in San Marcos and when the vegetation we discussed gets started in my forage pond, I will take you up on the offer of sending a picture for identification.

Dave
Posted By: Kelly Duffie Re: Duckweed control? - 04/17/03 01:23 PM
Hello Dave. Enjoyed visiting with you in San Marcos as well. Besides the legally improper labeling issue, small-packaged "Garden-Labeled" rotenone isn't what I'd call an economical option for such covert purposes. One website that I found lists a 12 oz. container of Rotenone 5% Powder at a $15.93/lb. equivalency. Fish-control treatments generally require about 10 lbs. of 5% rotenone powder per acre-foot. Based on this info, it would cost approx $637 to effectively treat a small 1-acre pond with a 4' avg depth. Not exactly what I'd call cheap - especially considering the very real risk of being shot, labeling-laws and the amount of time and manual labor required; not to mention that you can legally buy a lot of fish at the market with that kind of money. However, I'm pretty sure that spoons are the typical eating utensil in prison. For one's own legal purposes, it would be well worthwhile to obtain the appropriate license. Otherwise, hire the job to a professional. It is the private-market's circumvention of pesticide label-laws that will quickly bring an end to private pesticide availability - ie. chlordane, Dursban, etc. KD
Posted By: lakedoctor Re: Duckweed control? - 04/17/03 02:59 PM
Looks like I ruffled your feathers alittle bit KD.I think that your post are packed full of all the info. that is needed to get somebody on the right track of solving their problems and as far as I have seen you have been right on the money with your advise.The one thing that I haven't seen in the post is some of the important advise that is a big part of making the right choise when treating a pond.Like I said saftey is the #1 priority.Shan was the only one that memioned the subject the fact that I might sound like a bartender when I shot my post from the hip was ment to prove a point.If there is advise handed out and it has health risk to a person or persons then it should always be included.The fact that nobody menioned that sonar should not be applied within a quarter mile from a potable water supply is leaving out alot of information about this product.There is this type of info with every chemical that should be included before a reader goes buys it and finds that they should not use it.The chance of somebody taking some advise from a post and using it sucessfully is great but it won't be if they end up sick or worse.Just something I just had to post.Gotta go get my drivers license renewed. DOC
Posted By: David Reed Re: Duckweed control? - 04/17/03 08:15 PM
A few years ago I was applying some granular STUFF
(not sure that remember the name)to my pond and I didn't have good enough eye protection. My house is less than 100 yards away. I ran to the house
got in the shower, held my eyes open under water for 20 minutes. The pain was still more than I could bear at this point I was screaming. My wife took me to the emergency room. I was afraid that I would be blind for life. Luckily the damage was not permanent but it could have been.
This is just my two cents worth on the fact that
you CANNOT BE TO CAREFUL when using chemicals.
Posted By: lakedoctor Re: Duckweed control? - 04/18/03 01:25 AM
Sorry to hear about your accident David.Did you have any training is this field before your accident?If not where did you get the advise on how to use this product.If you had it to do over would you be more interested in finding out more saftey tips?Would you hire a pro instead?If something like that happens to you It makes you think twice about the stuff you could have loss if things would have went the other way.I'm glad your ok and things worked out. DOC
Posted By: Kelly Duffie Re: Duckweed control? - 04/18/03 03:03 AM
Doc: Have you ever considered a political office? I'm smiling! and couldn't resist.....
No, my feathers are fine. It is Hollywood actors and actresses, who think they are more enlightened than us "common citizens", who ruffle my feathers.

David: Copper sulfate, aka "Blue Stone" -probably the "granular stuff" that you were using- is extremely caustic, with long-term or permanent damage very likely if it gets in your eyes. Goggles are too cheap not to use when applying products, particularly granular versions. Thanks for posting your experience. You may have saved someone from a similar agony.
Posted By: lakedoctor Re: Duckweed control? - 04/18/03 04:47 AM
MY FELLOW AMERICANS!Let me make this perfectly clear: I am not an actor. Or a politician. But I did stay at a Holiday Inn Express last night. We have beat this dead horse til it is even unacceptable to the fast food industry. So at the risk of being run out of office I would like to start this topic over at the top of the page. The topic I am speaking of is aquatic chemical safety. I am inviting all professional aquatic applicators & "Common Citizens" to weigh in with their own words on all chemicals-one by one-starting with Sonar. You guys write the posts & I'll pour the drinks. See you all at the bar upstairs. DOC
Posted By: Kelly Duffie Re: Duckweed control? - 04/18/03 02:15 PM
Doc: I'll vote for that! Thanks for the humor. Have a great Easter. KD
Posted By: David Reed Re: Duckweed control? - 04/21/03 01:13 PM
Lakedoctor-no I didn't have any training prior to using the chemical. Hiring a professional is always the best option. I was just trying a small area to see how well this stuff worked. I think the name of it was Aquathol granular. Anyway, it scared me, I will be much more careful in the future.
Posted By: Robert B Re: Duckweed control? - 04/21/03 02:35 PM
David,
Just for your info, they have changed the formulation of Aquathol Granular to a heavier and more concentrated product called Super K. I remember the dust from the Aquathol flakes and was cringing when I read your post. I think that you may have reminded some of us to be more careful with our PPE's.
Robert
Posted By: GB in MN Re: Duckweed control? - 04/29/03 12:28 PM
I have a small pond (about 85' x 45'). I want to use Reward. I plan to use a pump sprayer.
How much Reward per gallon of water?
How much nonionic surfactant per gallon of water?
What can I use for nonionic surfactant?
The Duck weed is not bad yet, but I need to get on it fast.
Posted By: shan Re: Duckweed control? - 04/29/03 03:44 PM
I get good results with one gallon per acre Reward on duckweed but two gallons per acre is not an uncommon application rate. It depends on the water chemistry and turbidity. Diquat is toxic to fish in soft water at 245 ppm. If your pond is 3 feet deep on average putting 2 gallons of Reward into your pond would be about 1ppm active diquat. Thats with mixing it very well, in reality most of the diquat will be bound by dirt particles. So you see it would take quite a lot of Reward to kill fish with diquat. (about 400 gallons in a pond your size if my quick figures are right)

When treating duckweed with Reward think of it like mowing the yard. One or two times per year wont look very good. keep an eye on the duck weed and treat accordingly. Dont let it cover the pond or you will be asking for oxygen problems after the treatment. As long as its not covering more than 20 % of the ponds surface you can spray weekly. If you get a thick infestation you will need to wait several weeks between treatments. allowing the weeds to fully rot away before spraying again.

with such a small pond you may consider an aerator to help with oxygen

You could probably get away with one pint to one quart Reward per gallon of water for sucessful control. You can usually find a surfactant at any local feed and fertilizer. Look for 90 % surfactant. You dont absolutely need surfactant but it will help.

thats my take
Posted By: Kelly Duffie Re: Duckweed control? - 04/30/03 01:24 AM
A 12.5 to 25% REWARD:WATER solution might be a little stout. You would only be able to use 16 to 32 gallons of this mix per acre (.37 - .75 gal/1K sq. ft.) while staying within labeled use-rates. That can be a tough challenge with hand-held equipment, without creating a drift-prone spray pattern.
Though everyone treats with widely varying water-volumes, 4 oz. of REWARD per gallon of water, applied at roughly 1.5 gal. of mixed-solution per 1K sq. ft. should be very effective. As mentioned above, use very clean water to mix with the REWARD. Also, CIDE-KICK II (d'limonene) @ 1 oz./gal. of mixture works wonders with REWARD.
ALSO: WEEDTRINE-D is a much diluted formulation of REWARD, with a price tag that may be a more easily digested by pond owners with less than 1/4-acre to treat (though much more costly per lb of active-ingredient). However, mixing rates for WEEDTRINE-D do need to be adjusted (upward) to allow for its lower amount of formulated active-ingredient.
Posted By: shan Re: Duckweed control? - 04/30/03 02:43 AM
good call KM,

I totally forgot about weedtrine, dont use it much. dont spray 1/4 acres ponds much.
Posted By: Kelly Duffie Re: Duckweed control? - 04/30/03 02:53 AM
We don't even carry WEEDTRINE-D, since it really is an expensive alternative to REWARD (except for very small treatment areas). But, it is an alternative to be considered.
BTW: There are some water-use restrictions that need to be observed with either formulation of diquat: namely livestock, irrigation and domestic uses. Terms of the use-restrictions are based on application rates; so read the label before buying the product.
Posted By: diana Re: Duckweed control? - 06/16/03 03:17 PM
This is the first year we are getting Duckweed. Our pond is about 1 acre and 13 years old. I'm not sure what causes this weed but any info in what causes it, how to track down the source and any control would be greatly appreciated.
Posted By: shan Re: Duckweed control? - 06/17/03 11:36 PM
Diana,

look no further than the name, its transported by ducks, geese and other wading birds. One small duckweed plant under the right conditions will replicate into a serious problem
Posted By: GB in MN Re: Duckweed control? - 06/19/03 04:41 PM
Diana,
If you duckweed problem gets bad, I would NOT go with Reward or other spot treatments. If you are like me you want to get rid of the duckweed so you can enjoy see "water" on your pond. Reward will not give you that solution. See my other post for reasons.

Guy
Posted By: shan Re: Duckweed control? - 06/19/03 06:25 PM
GB,
I see your point about the Reward but there are many situations where its the only option so I would discount it all together. sonar or avast will eradicate duckweed but if there is a good sized stream feeding the pond those products will not work. Reward is excellent at killing duckweed, it rarley eradicates the problem but I have eradicated duckweed with Reward. 95% of the time you need to look at Reward treatment on duckweed like mowing the grass, it has to be done often to keep it in check.
Posted By: diana Re: Duckweed control? - 06/20/03 03:39 PM
GB
If Reward isn't a option what do you suggest. My pond is completely covered and I'm getting worried about a possible fish kill.
Posted By: GB in MN Re: Duckweed control? - 06/20/03 06:27 PM
diana
I wish I knew! I'm just a person with a pond like you. I tried keeping up with the reward treatment like Shan said.

But after a while it seemed that reward was not even working. The first few times the DW (duckweed) turned brown and was easy to see was dead. But the last few times I have sprayed I have seen no change.

Even when you do kill it it stays on the pond until the next heavy rain washes it away. I tried reward for close to four weeks and out of that time, I had a clean looking pond maybe 3 days. And that was after the first spraying.

I may try Sonar next year but I'm not sure how to proceed. I post a question (Tried Reward... now what) but have not got any replys.

Good luck to you Diana, if you learn something PLEASE let ME know!
Posted By: shan Re: Duckweed control? - 06/21/03 12:05 AM
GB,

are you mixing your spray mixture with pond water. if so try it with clean tap water, also use a good surfactant.

Sonar or Avast will eradicate duckweed as well as all the other aquatic plants in the pond. just simply pour it in the pond in a few places, it will do the rest. the only drawback to these chemicals is that they are very slow acting, it takes around 90 days to see results. so if the pond has a creek feeding it, the herbicide will probably be washed out before it has a chance to work. If your pond has no creek coming in and a small amount of water flow then Sonar or Avast will work great.

Also if you have flowing water you can keep adding Sonar/Avast monthly to keep the floridone concentration high but its very costly.
Posted By: Greg Grimes Re: Duckweed control? - 06/21/03 12:35 AM
In high flow rate situations you can setup a temp. siphon or rent a pump and pump the pond down a few feet prior to Sonar app. We then treat the exposed shoreline with Reward to kill duckweed on the edges. When this has been done SOnar has eradicated 83% (5 out of 6) of the ponds heavily infested with duckweed. We have also eradicated it when the pondowner stays on it with Reward and surfactant at proper rates. Good luck, I hate it for pondowners when all of a sudden they have duckweed and are forced into spending some serious time and money to have their pond back.
Posted By: GB in MN Re: Duckweed control? - 06/21/03 12:08 PM
Shan, I have been using well water to mix and added CIDE-KICK. And like I have said, even if I went out and sprayed every other day I would still need to rely on a heavy rain or skreet it to get a nice looking pond.

I think at this point I have conceded defeat once again for this year. I will try SONAR early next year and pump down the pond like Greg suggests. How long can I expect Sonar to last, I have heard it is good for 4 to 5 years. My pond fills with runoff so any rain I get, the pond fills pretty quik and then runs out once full. Will that cycle out the treatment after the first year?? If so I think I may be SOL. I can't afford to spend $500.00 plus on my pond every season. It would be cheaper in the long run for me to fill it in and have a nice little water garden.
Posted By: shan Re: Duckweed control? - 06/21/03 08:47 PM
thats weird, I have never heard of Reward not working on duckweed. Are you sure its duckweed. there are several types of floating plants. one common problem I have when folks call is mis-identification of plants

with that said, you need to figure out how much water if flowing out of the pond. catch the water in a bucket and time it. lets say you get 5 gallons in 5 seconds. thats one gallon per second. mulitply that rate out to see how much water is flowing out of the pond in one day, then one week then one month.

one acre of water 3 feet deep is about 1 million gallons of water. figure out how much water is in your pond. once you know how much water is in the pond and how much is flowing out you know how long it takes for the pond to flush. Add recommended rates of Sonar or Avast a week or so before the pond is flushed.

Sonar does not last for 5 years, I dont have a label in front of me but I think its more like 18 months, provided the pond does not flush. Draining the water can can help but it depends on how much water flow you have. if you drain it down and it fills back up in 2 days I would not worry about it, wait for the dryest part of the year, treat, and hope it does not rain much.
Posted By: Greg Grimes Re: Duckweed control? - 06/22/03 01:31 PM
GB I think the key is having a good concentration of SOnar for the first thirty days. I try all efforts to increase that chance, draining and watching the weather. If it is going to rain heavy in a week, wait. ALso better to treat before it gets too hot. Kelly Duffie may add a comment on this, but I feel SOnar can work great on Duckweed under the right circumstances, (best way to eradicate). However, I find it hard to believe it will stop duckweed or other invasive plants after about 6 months of the application, much less 5 years, I mean how is it concentrated enough after the pond has received flows for a few months?
Posted By: GB in MN Re: Duckweed control? - 06/23/03 11:40 PM
Well with your two comment I think I am just out of luck. There is no way I can afford to treat with Sonar unless It's going to last a few years.

What I don't understand is how I can drive a few minutes down the road in any direction and see a number of nice clean ponds of all sizes (smaller and lager than mine).

Why the hell don't they have a weed problem!

I really hate it. The pond is an eye sore except for about the two to four weeks after the ice goes out.

I don't know if I can get the white carp I see people talking about here or if it would even help. I know I would have to restock eack year due to freeze out.

I dunno, I think if I can find a constuction site looking for a place to get rid of clean fill, I may just have the perfect spot for it.
Posted By: Greg Grimes Re: Duckweed control? - 06/24/03 11:17 AM
Sorry to keep bringing bad news but the grass carp will not control duckweed, either. I see ponds that are right beside each other, one with a weed issue the other just fine. That is what keeps this job interesting.
Posted By: Fishhead Re: Duckweed control? - 06/25/03 04:17 PM
GB, I think I read most of the replies to you problem but the duckweed has to be feeding on something. Is it possible that a septic system is close to your pond and feeding it?

FH
Posted By: GB in MN Re: Duckweed control? - 06/25/03 08:55 PM
Yea it gets plenty of food. The whole pond is filled with runoff from numerous neighberhood yards. I mentioned that my very first questions the this forum. I said I could could probable re route the runoff to go aroun the pond. But it seemed most thought the fertilizer that I would be getting from the yards is only a small part of the problem.
Posted By: Robert B Re: Duckweed control? - 06/26/03 03:35 AM
If I remember correctly from my college Botany, the main limiting factor for duckweed is phosphorous. You could add aluminum sulfate to the pond to strip it out, add a bacteria blend especially to reduce phosphorous(I think I saw some in Aquatic Ecosystems), and try to limit new influx in the future.
Robert B
Posted By: Paul Graham Re: Duckweed control? - 07/19/03 04:49 AM
Has anyone heard of using a large fountain to control duckweed? I read in the local paper last year about a small pond in a city park that had a terrible case of duckweed. The city didn't want to use chemicals, so instead they put a large standard floating fountain in the middle of the pond and run it much of the time. There is no noticable duckweed in the pond any more.

My theory is that the surface action created by the water splashing back down pushed the duckweed to just limited shoreline areas like a good wind can do. Since the duckweed was then constantly pushed to just a tiny bit of shorline it eventually died off.

Is this just a pipe dream? Do you think they must have done some other treatments that the paper didn't talk about? Have you heard anything like this?

My grandmother has a pond with an awful awful duckweed problem and a solution like this would appeal to lots of relatives who don't want to use chemicals and would love the aestetic aspect of a nice big fountain in the middle of the pond.

Thanks.
Posted By: Greg Grimes Re: Duckweed control? - 07/20/03 12:35 PM
I've treated several ponds having duckweed very thick just not in a 50 foot area around the fountain. I have never seen it get rid of duckweed. Also I have been using a herbicide enhancer "growth stimulant" along with Reward. It appears me and the pondowner through about 4 treatemtns have rid of both duckweed and watermeal in two ponds this summer this way. Fo rinfo in one pond... Total herbicide cost of $325 for a 4 acre pond badly covered with watermeal back in APril. Good luck.
Posted By: Kelly Duffie Re: Duckweed control? - 07/21/03 03:39 AM
This must be the thread that never dies.

Greg: How does a growth stimulator enhance a herbicide that works by rapidly rupturing plant tissue at the cellular level? I've heard of using stimulants/enhancers with hormone-type of herbicides, but not with diquat. D'limonene does increase diquat's activity, but not through growth stimulation. Just curious as to which enhancer you were referring. KD
Posted By: Dudley Landry Re: Duckweed control? - 10/17/03 01:16 AM
Controlling duckweed can be accomplished. I hired an airboat sprayrig and using Reward, destroyed about 75% of the infestation. Then, using a fine-mesh net, physically removed as much as possible. As wind moved the remainder to the bank, I sprayed with Reward, using a fine mist spray. My eight acre pond is now 99.99% clear and I'm working on that last .01%.
Posted By: Ed Richter Re: Duckweed control? - 05/20/04 12:16 PM
This may be a stupid question, but why is duckweed bad? It is sold in aquarium stores to provide shade from the sun, food for the fish, and even good hiding environment for fish fry. I wouldn't want to swim in it, but everything else seems desirable. Seeing how much money and effort people spend on getting it out of their pond, I will hold off on putting it into mine.
Posted By: BrianH Re: Duckweed control? - 05/20/04 04:27 PM
Let me tell you how bad duckweed can be. I had an over fertile pond from cattle runoff. First the pondweed and algae grew pretty thick. The the duckweed covered 90 - 95% of the pond. That shaded the pond like really cloudy days in Auguast. My oxygen levels dropped (I don't have a meter, just watched how my fish stopped eating and hung near the top). I would then go out and fill my john boat with it and my fish would start eating again. I had to do it every week or I had problems.
I'm planning to drain, clean and divert water and start over with well water.
I HATE duckeeed.
Posted By: Dudley Landry Re: Duckweed control? - 05/20/04 11:12 PM
I'm still fighting that last 0.01%. As wind concentrates it against the bank, I dip it out, wait until the wind velocity decreases then spray the remainder with a diquat mist. I believe that my last words will be "Help me to the pond so I can spray that ******* duckweed."
Posted By: bank em Re: Duckweed control? - 07/12/04 02:16 PM
For me as a duckhunter, duckweed is the greatest thing around. I have one small pond, 3/4th acre that i try to keep the duckweed in although its not easy. When i have lots of duckweed i have lots of Gadwalls and wood ducks. Unbelievably, the bass still live in this pond even though it gets full duckweed coverage at times. I have other ponds to fish so i try to keep this one covered thick.
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