Frankfort, KY -  The long days of sunshine and heat promote the growth of plants, as anyone who goes on vacation for a week and returns to a jungle of a yard knows. Farm ponds grow a green ring around the banks during summer that in most cases is a nuisance for fishing and swimming, but provides cover for fish and is generally not a problem.

Sometimes, the green ring grows over the entire pond and makes it useless for fishing, swimming or even sitting in a lawn chair and admiring on a summer evening. A pond covered in a green mat of vegetation looks repugnant to the eye: unclean and stagnant. In addition to the aesthetic impact, excessive vegetation also can promote the overpopulation of bluegill because bass can’t get at them and oxygen depletion as the plants decay.

If your farm pond is covered in a thick mat of green goo or choked with bright green oatmeal like flowers, you must first figure out what vegetation is overtaking your pond in order to control it.

"The biggest deal is to identify what vegetation you are trying to get rid of so you select the correct control," said Kerry Prather, central fishery district biologist for the Kentucky Department of Fish and Wildlife Resources and an expert at farm pond management.

Some landowners shy away from using chemicals on their ponds and try a biological control by using triploid grass carp while some other landowners want quick results by using a chemical control. The best control may be a combination of both chemicals and grass carp.

"One chemical won’t kill everything," Prather explained, "and grass carp may not eat everything in your pond that is causing problems. Some landowners use chemicals at first to get a quick control and use triploid grass carp to maintain the control."

The ugly, green cotton like floating mats of filamentous algae is one of the main culprits in taking over farm ponds. Treat filamentous algae with Cutrine-Plus, K-TEA, Hydrothal 191 or copper sulfate. Triploid grass carp will eat this plant for the first year or two after stocking. Filamentous algae is what most people call "moss."

Triploid grass carp are good controllers of submerged vegetation such as curly-leaf pondweed whose leaves look like green crinkle cut French fries. Another common submerged vegetation in ponds is coontail. Coontail vegetation looks like it sounds; the ends of the plant form a bushy "tail." Other submerged vegetation found in farm ponds are milfoil, common naiad and muskgrass. Shading the plants with black plastic for two to four weeks kills submerged aquatic vegetation, but only shade small portions of the pond at a time. Chemicals such as Reward, Avast!, 4-D, Komeen, Weedtrine and Aquacide controls submerged vegetation as well.

Emerged vegetation such as cattails, water lillies, creeping water primrose and floating leaf pondweed can be controlled by the application of chemicals such as Rodeo, Reward, Aquacide and 4-D. Triploid grass carp are not a good control for these types of plants.

Floating aquatic vegetation are the hardest weeds to control in a pond. Triploid grass carp will not control these types of aquatic plants. The tiny bright green to whitish plants that look like tiny pieces of oatmeal are called watermeal while a similar plant that is larger with fine tentacles hanging from their bottom side is known as duckweed. Avast! and Sonar are both good chemicals to use to control these plants.

Chemical applications must be done carefully in order to protect your farm pond. Follow all instructions from the chemical manufacturer and some chemicals may prohibit the use of the pond for irrigation, livestock watering, swimming and even fishing and fish consumption for a period of time after application. Treat only sections of the pond at a time. Being too aggressive with chemical application may kill off so much plant life that it ties up oxygen in the water that can lead to fish kills. Most chemicals should be applied in water above 55 degrees.

Another easy to do control is to manually remove problem aquatic plants in early spring before they reproduce. A garden rake, dragging a heavy cable or chain across the bottom of the pond, pulling by hand or mowing with a scythe all help control aquatic plants. Aquatic plants contain good amounts of nitrogen and phosphorus so they may be tilled into your garden or applied to a compost pile.

For more information about fixing farm pond problems, call (800) 858-1549, and request the Farm Pond Management booklet, free from the KDFWR.

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