02-07-1977 Planning Packet - Laserfiche WebLink

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JK>'w. ;r". r- if ‘ ., '’: • . r’-.SW ¥ •«>--6- ChMiioal control of aquatic plants with liarbicldas is tanporaiy and control ■ensures usually must be repeated each year. Before chenlcal control is initiatedf proper identification of the nuisance regetation is necessary. Most aquatic herbi cides are selective as to the kinds of plants on which they are nost effective and the proper herbicide should be used for the plants at hand. The plants that a particular herbicide will control are listed on the label, ibcact species identification nay not be required but it is necessary to nake distinctions between major types of plants and often to identify the genus or general group of plants. The pictures of plants at the end of this publicaticn will aid in the identification of species oonaon in Minne sota. Belp in the identification of plants can be obtained fron the Minnesota Division of Game and Fish, 390 Centennial Building, St. Paul, Minnesota. Plants sent in for identification should be dried between sheets of newspaper or paper towelling. Care should be taken when applying herbicides for aquatic plant control so that the chemical or drift (spray or dust) from its application does not come in contact with adjacent upland vegetation. Shoreline areas should not be treated during periods of heavy wave action or the chemical may drift out of the treatment area or become so dilute that control will not be achieved. Cans or other containers of chemicals ehould be disposed of with care. Instructions on the label should always be read carefully. Chemicals listed herein are safe for fish when used according to label instructions. Label instructions should be followed in detail to avoid harm to per sons handling the chemical, harm to shrubs, lawns and gardens through irrigation and ham to humans, wildlife, livestock and pets that might use a treated area. Be- strictions on use of a treated area ehould be adhered to for the period of time specified on the label, or by the Department of Natural Resources. ✓ Chemical control of submerged and floating-leaved plants Organic herbicide commonly used for control of submerged and floating-leaved plants contain formulations of endothall, diquat, silvex, and 2,4*D. These are all biodegradable organic compounds. They eventually disappear from the water because they break down into simpler substances, they are tied up in bottom soils, and are absorbed by plants. I There is no single approved chemical that will give satisfactory control of all submerged and floating-leaved plants. The plants that a given herbicide will control are listed on the product label. Qidothall and diquat formulations should be applied early in the growing sea when the plants are actively growing but before they are in flower and fruit. This is commonly during late Nay and June. Diquat should not be used in muddy water be cause it is deactivated by silt particles. Following treatment with these compounds, plants usually turn brown in a few days and eventually settle to the bottom. Formulations of 2,4-D and silvex are slower acting growth-regulator tyi>es of killers and therefore should be applied earlier in the growing season. Granular 2,4-D products cw be applied as soon as the ice goes out in the spring. When liquid 2,4-D or silvex is used on floating-leaved plants, a wetting agent should be added to the spray solution. It may take from 4 to 6 weeks to show results when using 2,4-D or silvex. Wind and wave action sometimes cause chemically-killed plants to accumulate on shore. Water in a treated area may turn brown temporarily due to decay of plants and in some instances an algal bloom nay be fostered by nutrients released when the chemically killed vegetation decays. A large mass of decaying vegetation can also lower oxygen levels and cause a fish kill. For this reason, large scale chemical re moval of vegetation is usually undesirible. f *1