I have a 3/4+ acre pond in N. TX and it is significantly higher than other ponds in the area and the lake it used to join. It is about 90% covered with lilies[12-16in. diameter]and is infested with hydrilla.
I had been wanting to cut both of them out with my weed razor[spreading hydrilla no concern as I have 100% infestation], but the lilies are protecting my water levels and now fish are a secondary concern as the water is used for cattle.
I feel that the lilies really may be making the difference.
I would like to eradicate the hydrilla but keep the lilies.

How are the lilies (undoubtedly American lotus) protecting the pond's water level?
As for mechanically "controlling" hydrilla, understand that hydrilla is one of the few invasive species that just might be capable of creating a 110% infestation (or so it would seem). Keep in mind the source of Hydrilla's name: The Hydra, in Greek mythology, was a monster with nine heads, each of which, when struck off, was replaced by two new ones.
I'm certainly not against American lotus, providing it doesn't get out of hand. In fact, lotus makes excellent cover - especially its shade.
I'd suggest a low-dose (10-15 ppb) fluridone treatment next spring (Mar/Apr), which should control the hydrilla - and possibly thin the early-season lotus crop (from seed germination). Then, if needed or desired later in the season, use a targeted/topical application of glyphosate, imazapyr or 2,4-D to treat corridors through the lotus - to produce great "weed edge" fishing.

Kelly Duffie,
Sorry so long to get back to this. I had an emergency regarding a property dispute that took my full attention.

The lilies are protecting the pond from evaporation because they protect from direct sun and wind contact.[my hypothesis]
Thank you for your control advice. There are so many ideas out there. I have been doing weed razor manual removal and I am strong and able but it is one heck of a job!
The pond used to be full of fish and now it seems inactive at best.

plants also lose water through transpiration, probably counteracts any evaporation reduction.

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Question????

Wouldn't Grass Carp control the Hydrilla and not the Lilies??


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results vary greatly from pond to pond and state to state but generally I wouldn't rely on Grass Carp to "control" any vegetation. They may help keep it in check but Hydrilla just grows too fast.
And they should eat Hydrilla before they eat Lotus.

GAC

I am a Newbie with limited experience. But I have had good luck with Grass Carp and Hydrilla. I mechanically removed most of the Hydrilla and then released some 10 inch grass Carp. After 3 years the pond is Hydrilla free.

Permitting here in Florida for Grass Carp is now a Pain in the Butt. 3 years ago I could apply on line and print the permit at the same time. Now it takes an act of congress.

what are stocking rates for you guys? We're maxed at 7-10 fish/ac on the average and all fish are triploid.