Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Best Solution for hydrillia

Hi Guys
I have a 10 acre tank in the dallas, tx area that has an average depth of 8 foot with a max depth of 16-17 foot, water clarity is 4-6 feet. The hydrillia is terrible, it covers 75-80% of the pond all the way up to the surface. 2 years ago we put in 75 grass carp that are about 15 - 20 pounds now, maybe pushing up to 25 lbs. also 20 kio that are in the 10 lb range. they have not been able to do anything. the pond is still grossly consumed with hydrillia. i have been reading the forum and it seems sonar would be the best bet, but there is no way i can afford it. what other options do i have? how does the blue dye work? how much impact does it have on your fish population? If i use the blue dye what is the best time of year to put it out?

Thanks for any advice yall can give me.

Welcome to the forum...

I'm not the most knowledgeable on Sonar application or other alternatives to include dye but I can tell you pond dye does affect the food chain by blocking out sunlight that both the hydrilla and phytoplankton use. Phytoplankton is the foundation of your pond's food chain.

Koi do not feed on aquatic vegetation like grass carp do, so the stocking of them is not going to affect the hydrilla. Koi or nothing more than fancy colored common carp. You may be able to stock more grass carp to assist in the removal of hydrilla. It sounds if you have clarity of 4-6 feet you do not fertilize. Starting a fertilization program and dropping the water clarity to the 18" range would be a better option to the dye and would accomplish the same thing while also helping your fish out. The increased fertility would block sunlight to the hydrilla and keep it in check.

Let's see what others recommend though...

I don't have any direct experience with grass carp, just what I've gathered here. I do remember seeing that the larger the carp, the less effective they are on problematic weeds. I wonder if you would see the best results with a 2 pronged offensive, both reducing the clarity of the water with a photoplankton bloom and a restocking of smaller grass carp.

Here's a good pamphlet on grass carp. Pay attention to what they have to say about the numbers of fish to stock according to the amount of weeds to be controlled, water temp, and when to re-stock. You'll need a permit and can only stock triploids. The good thing is that Hydrilla is a preferred forage for the Grass Carp.
SRAC Grass Carp Publication

First thing is we need to properly identify plant species that you are dealing with. I have been managing aquatic vegetation for 5 years in North Texas and southern Oklahoma and have yet to see an actual Hydrilla case. Once we id plant we can come up with a game plan to manage plant.

There are basically three different management options for plants. Biological, which you have tried with grass carp, physical removal and EPA registered aquatic herbicides. Each is a tool that we can use to manage plants. Sometimes one works better than others.

I would avoid fertilizing until then. I would be happy to help you come up with and implement a game plan to manage those plants.

Also no expert but I've had first hand experience in dealing with Elodea. I originally was calling our pond weed Hydrilla until I learned how to distinguish between Hydrilla and Elodea, it turned out we have Elodea. Ultimately I used a Cutrine Plus/Reward combination that had a significant impact on our Elodea problem. Now all I do is spot treat areas each year. I believe I spent about $300-$400 to treat our 3 acre pond that had 70 to 80 percent coverage. It worked wonders for us. For a 10 acre pond I think I'd find out what a professional consultation would cost. Call/Email/PM Chad, I'm sure he'd be more that happy to discuss the cost/benefits of various alternatives.

Ditto on Chad's comments. ID is critical. If hydrilla wasn't introduced to your lake (accidentally or intentionally), then it is probably something else. Verify the plant's ID before you do anything.
IF it is hydrilla, fertilizing to shade it out is not an option (IMO). Hydrilla is capable of withstanding extreme low-light conditions, which is why it typically dominates plant-communities. Also, fluridone (Sonar, Avast, Whitcap) might be more affordable than you think (despite the high $/gal price-tag), considering the low-dosage required for excellent hydrilla control. Then again, your lake's hydrological characteristics have a lot to do with making it a decent candidate for fluridone treatments (little or no flow-through for 90+ days after treatment is essential).

Hey Kelly Duffie is back!!!

Where ya been stranger?

It's good to have you back Kelly thanks for coming back and posting!

Yep afraid to post after a KD comment, glad to see your post.

yes id first but we have had great results with a one two punch. Grass carp and copper/reward combo as mentioned by JHAP (informative post my friend).

It is a 350 acre lake and we keep less thatn 2% coverage. Every three years stock 2-3 grass carp per acre to keep fresh young hungry grass carp going. The initial stocking 8 years ago was about 8/acre. Also key to stock larger 11" plus size to survive bass predation. Then we spot tret with 2 gals reward/1 gallon ktea/.5 gallon surfactatn per weeded acre.

I think FFT you did not stock enough or % eaten by bass or escaped. I suggest more grass carp in the spring before the hydrilla starts back. Then spot treat early as suggested. Hope this helps.

What is that, like 27 1/2 now?

is there a plaace to go to find out what kind of plants you have in your pond na dhelp id them