Eddie Baggs

Algae is very common and will be present in all water that is exposed to the sunlight. Sometimes, however, this common inhabitant of water can become overwhelming in farm ponds.

There are three main types of algae in ponds:

n Chara is a branched algae that resembles flowering plants. It has musky odor and a “crunchy” feel, and is totally submerged.

n Single-celled and colonial algae include microscopic phytoplankton species that occurs in plankton blooms and are usually considered desirable as part of the food chain in fish production.

n Filamentous algae is commonly considered a nuisance and is seen as a mass of threadlike filaments. It has been described as a mass of wet wool or bright green hay. These types of algae are the most likely types that pond owners will be confronted with.

Filamentous algae can be raked or seined from the pond’s surface. This is generally recommended as a first step to control it since it is obviously the “cheapest” method.

Another “mechanical” meth­od of control for algae is an Aquashade product. Aqua­shade is a nontoxic dye or colorant. It will prevent or reduce algae growth by limiting sunlight penetration. Caution, though: These products may suppress the natural food chain of the pond.

Biological controls for algae would include either grass carp or tilapia. Both of these fish will require a license from the Texas Parks and Wildlife (www.tpwd.state.tx.us). Tilapia will readily consume filamentous algae, but are a warm-weather species that will not survive in temperatures below 55 degrees. This may reduce the effectiveness of tilapia in this area because stocking might be delayed due to weather issues. Grass carp will consume filamentous algae, but it is not their preferred food. They will consume other aquatic vegetation first.

Chemical methods of controlling filamentous algae are usually successful and include copper-based compounds, alkylamine salts of endothall and diquat. Copper sulfate or “bluestone” is the most common treatment. It comes in several forms, but the smaller crystals will dissolve more easily than the larger crystals. This treatment will be less effective in very hard water as it will bind with the calcium present.

Cutrine Plus, K-Tea, Cap­tain, Algae Pro, Clearigate and others are all chelated copper herbicides that are also able to control filamentous algae. All copper compounds can be toxic to fish if used above labeled rates or if they are used in soft or acidic water. Hydrothol 191 is an alkylamine salt of endothall and acts as a contact herbicide. This means that is it will work quickly and kill all plant cells it contacts. It can also be toxic to fish.

Pond design and construction can be the most significant method to control unwanted aquatic vegetation. To learn more about these topics contact your local AgriLife Extension office or Natural Resources Conservation Ser­vice office, or go to the “Pond Manager Diagnostics Tool” Web site at http://aquaplant.
tamu.edu.

The Denton County Beef, Crops and Forages Committee will sponsor a “Pond Man­agement Workshop” at 5:30 p.m. Thursday at Rancho De La Roca in Aubrey. Pre-registration is due by Monday with a fee of $10 per person. Call the Extension office at 940-349-2880 for more details.

EDDIE BAGGS, county extension agent with the Texas AgriLife Extension Service in Denton County, can be reached at 940-349-2880.