Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Severe Eurasian Watermilfoil Problem

Hello folks, I'm a newbie to the board and a semi-newbie in the world of pond management. I have a 6 acre irregularly shaped pond. The north end (shallow end) is 3'-6', the south end (deeper) is 6' to 15' deep. I have owned the property for 2 years now.
My problem is a very nasty Eurasian Watermilfoil infestation that went from around 25% of the pond last year to virtually 100% this year. There is also a population of Coontail, but not nearly as bad as the milfoil. From lurking for a while and reading incessantly, I surmise that it originated from a bass boat a friend of mine brought in to make me a depth profile of the pond shortly after we bought the property. It seems that that was a major mistake on my part. We treated with granular CuSO4 and Reward last year and this year also. NOT EFFECTIVE. It knocked it down somewhat and it returned with a vengeance both years. The water in the pond is crystal clear and we have very good circulation in this pond with prevailing winds. Algae gets to be a minor problem in late July and August when the water warms > 75-80 degrees but is easily alleviated with granular copper sulfate. The milfoil has reached monster proportions late this summer and there is a mat over around 25% of the pond and the growth makes it virtually impossible to navigate the pond in a boat with a trolling motor.
I would like to permanantly eradicate the milfoil. Sonar sounds like a good choice, but I have 2 exit tiles feeding into a creek that runs south of the pond. I was wondering about using 2,4-D. My reading on other sites tells me that it is pretty much specific for milfoil. The pond is 15 years old and stocked with largemouth bass, hybrid bluegills, black crappie, yellow bullheads, channel catfish, and a variety of bluegill that resembles the georgia giant.
Any help or suggestions for the eradication will be greatly appreciated, as well as the application rate or total amount per acre needed. The average depth of the pond is 6 feet as determined by a Purdue Extension Agent.
Thanks in advance for your knowledge!!!

Bassman, Welcome to the forum!

I don't know much about aquatic plants--My pond has zero vegitation!

Will white amur (grass carp) eat milfoil? I know that tilapia will, but not sure if they're legal in your state. Alum will help lessen the growth of all plants temporarily by binding up the soluable phosphorus. You may want to try a combo approach.

Personally, I stay far far awy from the copper sulfate due to the long term heavy metal problems it causes.

With those nasty little bullheads, you're a very lucky man to have clear water.

I forgot to mention that I have what seems to be an adequite population of grass carp. They seem to be dying off though. Have found 3 dead ones in the 3' to 4' range the last 2 years. From my reading, milfoil seems to be the last forage that the carp prefer. Any comments??

Also, I sould like to know the effects on the spawn that the chemicals used to treat the milfoil and coontail would have.

Thanks!

Just FYI also. Have caught LGB in the pond up to 8.5 lbs, channel cats caught up to 8 lb. Bluegills up to 11", black crappie up to 15". Not too many bullheads caught, didnt even know they were in there till this summer. Caught a BIG bluegill (11") that i believe is a georgia giant. Also the pond is located in the center of Indiana just for climate reference.

IIRC, Grass Carp are only effective when they are younger than four or five. The bigger, older ones are pretty much worthless for vegitation control.

Looks like its time to make a purchase then. To my knowledge these are most likely original to the pond. I'm assuming it's probably too late in the year to introduce more now, would spring be better?

Thanks for the response Rainman

Bassman70 Have you talked to anyone at Aquatic Controls in Seymour, If not give Matt Johnson at call at 800-753-LAKE ext 262 and I think they can help you.

Thanks for the information Ted, I'll be in contact with them.

Bassman70

Navigate at 100 lbs per acre will knock out milfoil, but you cant easily eliminate it completely with the granulars.

Fluridone, sustained at about 50 ppb for several weeks in June will do the trick. Can you block off the exit tiles during that time?

Bassman if you want to spot treat Milfoil I would go with Renovate OTF which was made for this weed in particular. You could also go with Sonar Q at 10 lbs per acre. Aquatic Control is a good place for info on chemicals but you can also go to

Here is the latest from Southeast Michigan regarding movement of invasive plants from the Detroit Free Press 0n 3/20:
Starry Stonewort is confirmed in 21 Mich. lakes, 11 in my county of Oakland. Experts fear this plant will be more troublesome than Eurasian W. Milfoil. They say the impact on the fisheries will be huge. The next is Fanwort which was confirmed several years back but has just recently started to spread. The say the herbicides used to kill this plant are not currently approved in Michigan.
Lastly, Hydrilla is sited to be found in one Indiana Lake 50 miles south of the Michigan line (wonder if it is near Cecils' place?).