Certain fish can help control a variety of aquatic plants

I commonly receive numerous calls during this time of year about controlling various aquatic plants in ponds; K-State Research and Extension has a great publication on this problem.

Control of aquatic plants depends on the type of water, species of plant, correct identification and water usage.

The most common problems occur in impounded waters such as ponds, lakes and reservoirs. Aquatic vegetation is seldom a problem in flowing waters such as rivers and streams.

Water saturated areas like marshes, seeps, and drainage ditches usually have little problems with aquatic vegetation since these areas are not used for conventional agriculture.

Problem weed species must be identified before appropriate control can occur; they are classified by similar growth habits.

Phytoplankton, filamentous and chara are the major forms of fresh water algae.

Some plants are free-floating while others, rooted in the bottom, have floating leaves that rise or fall with the water level. Many floating plants grow rapidly and are among the most troublesome aquatic plants.

Submersed plants are true seed plants with roots, stems, and leaves. Rooted on the bottom, these plants grow chiefly below the surface although their flowers and seeds and a few leaves may extend above it. A depth of 10 to 12 feet in clear water is the limit habitat for most submersed plants.

Emersed plants are rooted in the bottom and produce most of their leaves and flowers at or above the surface. Leaves of emersed plants do not rise and fall with the water level as do those of attached floating plants.

Marginal plants are emersed plants that grow on saturated soil beyond the water's edge. These plants vary in size, shape and habitat. They may be found growing in moist soils along shorelines into water up to two feet in depth.

Prevention, mechanical, biological, and herbicides are the four subdivisions of control. A combination of these usually works best.

Aquatic weed problems usually occur in clear, shallow water, high in nutrients. When planning for new ponds or lakes, shallow water areas can be minimized by shaping the sides with a 3 foot horizontal to 1 foot vertical slope.

Excessive nutrients should also be prevented from getting into the water since they cause rapid plant growth.

Mechanical and physical means will be more effective in smaller bodies of water. They are also labor intensive and provide results for a short time. These methods are extremely effective in home sewage lagoons.

Herbivorous fish are usually the most effective biological method of control. Stocking new ponds with three to five grass carp per acre can prevent development of aquatic weed problems.

Herbicides may be used for control, but results may vary due to stage of growth, rate of application, timing, and weed susceptibility.

Please contact the Extension Office or go to www.ksre.ksu.edu and search for "C-667 Aquatic Weeds and their Control" for more information.

Note: There will be an aquatic weed management workshop on July 21 hosted by the Southeast Kansas Weed Management Area, the Bourbon County Conservation District and the Bourbon County Extension Office. This session will take place at 6 p.m. at the Fort Scott Community College cafeteria.

Editor's Note: Delta George is a K-State Research and Extension agriculture and 4-H extension agent assigned to Bourbon County. She may be reached at (620) 223-3720.