Guide to weed control in lawns and other turf discusses methods of weed control, time of application, calibration of sprayers, dry spreaders, control of common weeds, and cleaning the sprayer

Martin, Dean M.

Parker, Robert

Peacock, James F.

English

Public Research Access Institutional Repository and Information Exchange

South Dakota State University Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange SDSU Extension Fact Sheets SDSU Extension 1969 Weed Control in Lawns and Other Turf James F. Peacock Dean M. Martin Robert Parker Follow this and additional works at: https://openprairie.sdstate.edu/extension_fact Recommended Citation Peacock, James F.; Martin, Dean M.; and Parker, Robert, "Weed Control in Lawns and Other Turf" (1969). SDSU Extension Fact Sheets. 1342. https://openprairie.sdstate.edu/extension_fact/1342 This Fact Sheet is brought to you for free and open access by the SDSU Extension at Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. It has been accepted for inclusion in SDSU Extension Fact Sheets by an authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For more information, please contact michael.biondo@sdstate.edu. Historic, archived doculllent Do not assume content reflects current scientific knowledge, policies, or practices. SDSU ® Extension For current policies and practices, contact SDSU Extension Website: extension.sdstate.edu Phone: Email: 605-688-4 792 sdsu.extension@sdstate.edu SDSU Extension is an equal opportunity provider and employer in accordance with the nondiscrimination policies of South Dakota State University, the South Dakota Board of Regents and the United States Department of Agriculture. Weed Control in Lawns and Other Turf FS 419 r FS 419 Weed Control • Lawns and Other Turf By James F. Peacock, Graduate Assistant in Weeds, Dean M. Martin, Extension Horticulturist, and Robert Parker, Extension Agronomist-Weeds One of the largest problems lawn keepers face is weed control. The best method for keeping weeds out of your lawn is to maintain a dense, vigorous stand of healthy grass. Such grass is able to effective-ly compete with weeds for moisture, plant food, light, and space in the lawn. Here is how to get a vigorous stand of grass: •Water when needed by soaking the soil to a 6- to 8-inch depth. • Mow to maintain bluegrasses and red fescues at a 1 ½-inch height. • Fertilize at least twice a year-once in the spring and again in early fall. • Control insects and diseases by applying the prop-er chemicals as needed. Poorly managed lawns are usually weedy, and well-managed lawns may occasionally have weed problems. These weeds may come from many sources. Most soils contain hundreds and often thousands of live weed seeds per square foot. These seeds are able to remain dormant in the soil many years until conditions are favorable for germination. Weed seeds are often brought in with topsoil, mulches, or manure. They may be carried to your lawn by wind, water, and even birds. Poor quality grass seed mix-tures may contain weed seeds that can cause prob-lems in your lawn. WEED CONTROL METHODS FOR LAWNS The two primary methods of weed control are mechanical and chemical. Mechanical methods in-clude the removal of weeds by pulling, digging, hoe-ing, cultivating, or other methods. These methods are useful where there aren't many weeds. Chemical methods eliminate weeds through use of special weed killing chemicals called herbicides or weedi-cides-a system useful for removing large numbers of weeds. This fact sheet is primarily devoted to chemical weed control. Types of Herbicides Herbicides are available in several forms: • Emulsifiable Concentrates-mix these liquids m water and apply as sprays. • Wettable Powders-mix these powders in water and apply as sprays. • Granules-apply these materials dry with a fer-tilizer spreader. • Combined with Fertilizers-apply by using a fer-tilizer spreader. •Wax Bars-drag this bar over the lawn on a warm day so that the wax impregnated with herbicide will rub off on the weeds. Time of Application Herbicides may be applied pre-plant, pre-emer-gence, or post-emergence, depending on the weed problem. A pre-plant treatment is applied before seeding your lawn. Pre-emergence treatments are usually applied to established lawns before annual weeds emerge. Post-emergence treatments are ap-plied after the weeds are up. Most herbicides applied post-emergence must be absorbed by the leaves of the weeds. Seedlings of all weed species are easier to kill than older plants of the same species. Also, weeds are easier to kill with herbicides if they are growing actively. Thus, the post-emergence treatment is more effective if applied during warm, moist growing conditions. Treat your lawn when the temperature is between 65 and 85 degrees and under good soil moisture con-ditions to get best results. Do not mow for 3 to 5 days before treating nor l to 2 days afterwards. Do not water for 24 hours after treatment. ADJUSTING APPLICATORS Calibration of Sprayer Most chemical weed killers will kill turf grasses as well as weeds if too much is applied. It is essen-tial to know the amount of material that a piece of equipment will apply on a given area. You can find this rate only by trying out the sprayer or spreader with water or some other harmless material. Do this calibration on the turf under conditions similar to those which will exist when you apply the chemical. Follow these steps to determine the capacity of your equipment. 1. Measure 1,000 square feet of turf ( a block 20 x 50 feet or equivalent), using twine to outline the block. (Most dosage recommendations are made for 1,000 square feet of area.) 2. Pour in a measured amount of water (for example, 3 gallons). 3. Pump up the sprayer to a reasonable pressure. (On a 2- to 3-gallon sprayer, 15 to 25 full strokes of the pump are suggested.) 4. Open the cut-off valve and walk at a reasonable pace over the block until all the surface is covered. 5. Release the air pressure and measure the amount of water left in the tank. 6. Subtract the amount left in the tank ( step 5) from the amount placed in the sprayer to find the amount used in spraying 1,000 square feet. Example: 3 gallons put in sprayer minus 2 gallons left === 1 gallon used to cover 1,000 square feet. The amount found in step 6 is the base for figuring how much chemical to use in each gallon of water when you actually spray. The actual amount of water used is not important, but whatever the amount, it must be a known quantity. Thus, if the suggested rate of chemical is 2 ounces per 1,000 square feet and your sprayer applies 1 gallon per 1,000 square feet, you mix 2 ounces for each gallon of water the sprayer will hold. For instance, a 3-gallon sprayer will take 6 ounces of chemical. Dry Spreaders 1. Measure 1,000 square feet of turf (20 x 50 feet). 2. Choose a setting on the feed-regulating device. 3. Weigh out about 5 to 10 pounds of the dry chemical and place in hopper. (Overdosage will seldom cause injury, but would be expensive.) 4. Open the feed and walk over the area until it has been fully covered. 5. Weigh the material left in the spreader. 6. Subtract the remainder from the original amount placed in the hopper to find how much you ap-plied to the 1,000 square feet of turf. 7. Since most dry herbicides are sold in a ready-to-apply form, you may have to change the feed set-ting and repeat the process on a different area un-til you find a setting which is correct for the amount suggested on the product label. These calibrations apply as much to the person using the equipment as to the sprayer or spreader. For that reason, keep your walking speed and the pressure in the tank as constant as possible. HELPFUL HINTS • Fallow the directions and safety precautions listed on the label of each chemical container. • Avoid prolonged contact of herbicides with your skin, and prolonged inhalation of herbicide dusts and mists. • Use the exact amount of herbicide recommended on the label or in this Fact Sheet. • Reduce drifting of chemical mists onto desirable vegetation at the time of spraying: 1. Spray only during the calm of the day. 2. Keep the spray nozzles close to the ground. 3. Use low pressures on your sprayer. 4. Use sprinkling can with proper spray mixture. 5. Cover desirable vegetation with cardboard boxes, canvas, plastic, or other protective cover-mgs. • Reduce hazards from drift of herbicidal vapors or fumes onto desirable vegetation after spraying has been completed: 1. Use low volatile form of herbicide to minimize drift of vapors given off after spraying. Amine and acid forms are less volatile than ester forms of sprays. 2. Leave protective covers in place several hours after spraying. • Clean your sprayer after each use. • Dispose of empty herbicide containers at a sani-tary land-fill, or crush and bury them at least 18 inches deep in a place they will not contaminate water supplies. COMMON WEEDS AND THEIR CONTROL DANDELION: Taraxacum officinale Weber.-also called blow ball, and puff ball. Dandelion, a perennial, reproduces by seed or by lateral crown shoots from a fleshy, deep taproot. Leaves are 3 to 10 inches long and have irregular margins. Bright yellow flowers are produced on up-right stems that may be from 2 to 18 inches tall. The seeds are attached to fluffy bristles and can be carried by the wind for many miles. Dandelions may be controlled with 2,4-D, 2,4,5-T, silvex or dicamba. Use 2 tablespoons of 2,4-D or 1 ½ tablespoons of 2,4,5-T or silvex or 1 tablespoon of dicamba on each 1,000 sq. ft. Calibrate the sprayer and mix the chemical in the amount of water requir-ed to cover 1,000 square feet. Spray when the dande-lions are growing actively. Do not spray dicamba in the root zone of trees and shrubs. COMMON CHICKWEED: Stellaria media (L.) Cyrillo-also called starwort, satin flower, and starweed. This weed is an annual or winter annual that is especially troublesome where there is partial shade, such as around shrubs, foundations of houses, and in gardens. The plants reproduce by seeds and by trailing stems that take root at the lower joints. Heart-shaped, fleshy leaves are arranged in pairs on branched stems. Flowers are small, white, and star-shaped. Numerous tiny, rough, reddish brown, flat seeds are produced in a seed capsule. Chickweed is difficult to control, but 2,4,5-T, silvex, or dicamba may be used successfully. Apply in May or early June before chickweed flowers. Use 1 ½ tablespoons of 2,4,5-T or silvex or 1 tablespoon of dicamba for each 1,000 square feet. Calibrate the sprayer and mix the chemicals in the amount of water required to cover 1,000 square feet. Follow-up Dandelion Common Chickweed Prostrate Knotweed treatments are usually required for good control. Do not spray dicamba in the root zone of trees and shrubs. PROSTRATE KNOTWEED: Polygonum aviculare (L).-also called knotgrass, dooryard weed, matgrass, and knot-weed. Prostrate knotweed, an annual, reproduces only by seeds. The stems spread in all directions from a small taproot and form a dense, close-growing mat. The bluish-green leaves are attached to the stem at prominent "knots or joints." Knotweed can be controlled with 2,4,5-T, silvex, dicamba, or a high rate of 2,4-D. Use 2 tablespoons of 2,4,5-T, 1 ½ tablespoons of silvex, 1 tablespoon of dicamba, or 6 tablespoons of 2,4-D on each 1,000 square feet. Calibrate the sprayer and mix the chem-ical in the amount of water required to cover 1,000 square feet. Apply when plants are growing actively. Do not spray dicamba in the root zone of trees and shrubs. MAJOR PLANTAIN: Plantago major L.-also called broad-leaved plantain, dooryard plantain, and common plantain. Major plantain, a perennial, reproduces by seeds and new shoots from the roots. The leaves are egg-shaped, 1 to 8 inches long, grow close to the ground in a rosette, and have 3 to 11 parallel veins. A large number of brown seeds are produced on a flowering stalk that may be 2 to 10 inches tall. Major plantain can be controlled by 2,4-D, 2,4,5-T or silvex. Use 3 tablespoons of 2,4-D or 1 ½ tablespoons of 2,4,5-T or silvex. Calibrate the sprayer and mix the chemical in the amount of water needed to cover 1,000 square feet. Apply when plants are growing ac-tively in the spring or fall. CREEPING BELLFLOWER: Campanula rapunculoides L. -also called bellflower and European bellflower. Creeping bellflower, a perennial, reproduces by seeds and thick, radish-like roots. The flowers are blue to purple, bell-shaped, and borne singly on the upper portion of the stem. The upper leaves are rough, egg-shaped, and taper to a long point, while lower leaves tend to be larger and heart-shaped. The stem is smooth with few or no branches and may be from 1 to 3 feet tall. Creeping bellflower is resistant to 2,4-D and silvex, but can be controlled with dicamba. Use 2 tablespoons of dicamba for each 1,000 square feet of area to be sprayed. Calibrate your sprayer and mix the chemi-cal in the amount of water required to cover 1,000 square feet. Spray when the weeds are growing active-ly. Do not spray this chemical in the root zone of trees and shrubs. GROUND IVY Glecoma hederacea L.-also called creeping charlie, field balm, and gill-over-the-ground. Ground ivy is a shallow-rooted perennial that is troublesome in shaded areas that are protected from direct sunlight. It reproduces by seed and creeping stems that form roots at the joints or nodes. The leaves are bright green, round, and ½ to 1 ½ inches in diam-eter. The leaves are hairy, arranged opposite along the four-sided stems, and have toothed margins. The small blue-purple flowers are funnel shaped and ar-. ranged in small groups. The seeds are rough, dark-brown, and appear in groups of four. Ground ivy may be controlled with 2,4,5-T, silvex, or dicamba. Use 2 tablespoons of 2,4,5-T or dicamba or 1 ½ tablespoons of silvex on each 1,000 square feet. Calibrate the sprayer and mix the chemical in the amount of water required to cover 1,000 square feet. ~ .. ~ fLO',VE, ITIIM .... 1Uf\E • -- •®G FLOWf.f\,PISTtLL WITHtRE'.0,6TAl'\EMS - c-- :::r ~ Major Plantain Creeping Bellflower Spray in the spring or fall when ground ivy is grow-ing actively. Do not spray dicamba in the root zone of trees and shrubs. CRABGRASS Digitaria sanquinalis L.-also called large crabgrass, watergrass, fingergrass, crow foot, and hairy crab-grass. Crabgrass, an annual, reproduces by seed and stems rooting at the joints. It appears during the hot summer months and is killed by a light frost. Crab-grass stems are erect or slightly prostrate. Leaves are 2 to 6 inches long and have scattered hairs on them and where they attach to the stem. The heads are usu-ally 2 to 6 inches long, and have from 3 to 10 slender fingers branching off at the top. The small, hairy, pointed seeds are round on one side and flat on the other. Crabgrass is easiest to kill if control measures are taken before it germinates. Applications of terbutol, bensulide, DCP A, and siduron have given good re-sults when applied before crabgrass germinates. Apply as directed on the label. After crabgrass is visi-ble in your lawn, it is more difficult to control. How-ever, MAA, and phenyl mercuric acetate will give good results. Apply according to directions on their labels. OTHER GRASSES-Green foxtail: Setaria virdis (L.) Beauv. and yellow foxtail: Setaria glauca ( L.) Beauv. may be controlled with pre-emergence applications of bensulide. Follow the directions on the label for crab-grass. Post-emergence control may be obtained with MAA when foxtail is 2 inches tall. Barnyardgrsas: Echi-nochloa crusgalli ( L. ) Beauv. is also controlled with DSMA if application is made before the grass is 6 inches tall. Use the amounts given on the label for the control of crabgrass. . Groundlvy Quackgrass: Agropyron repens ( L.) Beauv., brome-grass: Bromus inermis Leyss., and orchard grass: Dact-ylis glomerata ( L. ) are difficult to remove from turf. Herbicides that kill these grasses kill all lawn grasses. Infested areas may, however, be treated with amitrole-T. Use 5 to 6 tablespoons per 1,000 square feet. Treated areas may be reseeded in 5 weeks if the soil is thorough-ly tilled. , Crabgrass CLEANING YOUR SPRAYER Rinsing your sprayer with water and detergent is sufficient if the sprayer is not used for other pur-poses. If you plan to use it later for spraying insec-ticides or fungicides on desirable vegetation, clean it with activated charcoal or household ammonia. Common Names of Some of the Less Volatile Chemicals and Their Counterparts Add 1 ounce of activated charcoal and 2 ounces of household detergent to 2 ½ gallons of water and mix thoroughly. Operate your sprayer for about 2 minutes with this mixture in it and it will be clean. Common Names 2,4-D 2,4,5-T Silvex or 2,4,5-TP Dicamba Terbutol Bensulide DCPA Siduron in Brand Names Trade Names Weedone 638, Emulsamine 3E, Dacamine, Lithate, DSP Numerous Numerous Banvel Azak, Azar, Hercules 9573 Betasan Dacthal Tupersan When cleaning with ammonia, add 2 tablespoons of ammonia to 1 quart of water. Put this solution in the sprayer and spray a small amount through the nozzle. Allow the remainder of the solution to stay in the sprayer overnight. Then pour out the solution and rinse the sprayer twice with clean water, spray-ing a portion of each rinse through the nozzle. MAA, DSMA, AMA Ansar 184, Diamond DSMA, Clout, Ansar 157, Acme Crabgrass Killer Scud Phenyl mercuric acetate Amitrole-T Cytrol, Amitrol-T Common Lawn Weeds and Effectiveness of Several Herbicides for Their Control Control* Dicambat Silvex Weed Name Type of Plant When to Apply 2,4-D 2,4,5-T (Banvel) (2,4,5-TP) Bellflower, Creeping Campanula rapunculoids L.perennial 6P 2G Black Medic Medicago lupulina L. annual early spring 3F 3F 2G 3G Chickweed, Common Stellaria media annual spring or fall none l ½ G lG l½G Chickweed, Mouse-ear Cerastium vulgatum (L). perennial spring or fall none l ½ G lG l ½ G Cyrillo Dandelion T araxacum officinale perennial spring or fall 2G l ½ G lG l½G Weber Dock, Curly Rume crispus L. perennial spring or fall 2G l½G lG l½F Ground Ivy, or Creeping Charlie Glechoma hederacea L. perennial spring or fall 6F 2F 2G l½G Knotweed, Prostrate Polygonum aviculare L. annual sprmg 6F 2F lG l½F Kochia, or Fireweed Kochia scoparia (L). Roth annual spring lG lG lG Mallow, Low, Dwarf, or Roundleaf annual or spnng 3F 2F 2F Malva rotundif olia L. perennial Plantain, Buckhorn Plantago lanceolata L. perennial spring or fall 3G l ½ G none l ½G Plantain, Major, Broad-leaved, or Common Plantago major L. perennial spring or fall 3G l ½G none l½G White Clover Trifolium repens L. perennial spring or fall 6P 3G 2G 3G W oodsorrel, Yellow Oxalis stricta L. perennial 6P 3G *T abl espoons of chemical containing 4 pounds acid equivalent for use on 1,000 square feet to give P (poor), F (fai r) or G (good ) weed control. Use twice as much of a chemical containing onl y 2 pounds acid equiva-lent per ga llon or 1 ½ times as much fo r a chemical containing 3 pounds per gallon. -!-Do not use dicamba under shallow-rooted trees and shrubs. hsued in furtherance of Cooperative Extension work, Acts of May 8 an<l June 30, 1914, in cooperation with the Unite<l States Department of Agriculture. John T. Stone, Dean of Extension, South Dakota State University, Broookings. 5M -1-69 -File: 7.5-8305 COOPERATIVE EXTENSION SERVICE U. S. DEPARTMENT OF AGRICULTURE SOUTH DAKOTA STATE UNIVERSITY Brookings, S. D. 57006 OFFICIAL BUSINESS 5M -l-6?-8305 Postage and Fees Paid U.S. Department of Agriculture 

Weed Control in Lawns and Other Turf

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Weed Control in Lawns and Other Turf

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